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Full text of "Radio Electronics (October 1980)"

issembling the Unicorn-1 robot 
Els for LED bar-graph displays 
lihola Tesla-the pioneer 




YOUR OWN COMPUTER 
40-PAGE BUYERS GUIDE 




1980 



How to use flasher LED's 
Halter's super hi-fi amplifier 
One-IC digital panel meter 



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"71896"48783' 



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COOPER I BC^En'CSESCSrr'UBWN'NWKllSCiN-WElXER'WISS'XCELrre 




Success 
Forces 

Can you be successful despite 
yourself? Here's how I did it. 



"I made it despite myself. 



By Joseph Sugarman, President 
JS&A Group, Inc. 



It's a joke. I'm considered one of Amer- 
ica's top copywriters and mail order entre- 
preneurs. 

I never finished college, never took a 
course in business, advertising or creative 
writing, and even flunked English. 

On top of that, I failed at almost every- 
thing I did. My list of failures would fill 
an encyclopedia. 

Now you probably expect me to tell you 
that it was failure after failure until I hit 
upon the "wealth formula" or the "secret 
to success" or some other trite expression. 
Not true. 

ONLY SIX REASONS 

What I've found about success is quite 
opposite the formulas you've read about 
or the misconceptions you've heard. 

I simply took my few successes and 
many failures and discovered six reasons 
why I failed and six reasons why I suc- 
ceeded. 

The reasons I succeeded seemed like 
forces. Whenever I followed them, I 
achieved success. Whenever I didn't 
follow them, I failed. I soon called them 
Success Forces. 

I used Success Forces to build my busi- 
ness from the basement of my home into 
America's largest single source of space- 
age products. I was successful. But was 
it a coincidence or was it a direct result 
of Success Forces? I really didn't know. 
MATERIAL THINGS 

If you measure success by material 
things, I achieved quite a bit: several 
cars, airplanes, snowmobiles, motor- 
cycles, four beautiful homes- all the 
material things I imagined I'd ever 
want. 

And I had recognition. My success 
story was written up in several maga- 
zines. But it wasn't until after I revealed 
my Success Forces in a few speeches that 
I realized my concept would work for 
others. 

I was getting letters from people who 
told me how one of my Success Forces 
had changed their lives. Others told me 
of how they used Success Forces to make 
extra money or achieve greater happi- 
ness. Still others who always thought of 
themselves as failures, became success- 
ful despite themselves. 



But the whole thing seemed strange to 
me. Was Success Forces original? Some- 
thing like it had to be in some other 
success book. So I read. I bought every 
success book I could find. I studied Chi- 
nese philosophy. I bought every motiva- 
tional cassette that was offered. And I 
thoroughly studied the material. 

I then discovered why my concept was 
indeed different. Success Forces lets you 
be yourself, and guides you towards 
making simple choices that can ulti- 
mately change your life. If you make the 
right choices, you are literally forced into 
success. 

MY $2,000 SEMINAR 
Although I was convinced that my con- 
cept was different, I wanted to be abso- 
lutely sure it would work. I decided to 
conduct a seminar with a select group of 
16 people who would be willing to pay 
handsomely to learn my philosophies. 
My five-day seminar cost each partici- 
pant $2,000 and I held eight of them. All 
were sold out. 

The success stories resulting from each 
seminar are already history, I taught a 
Texas farmer, a New Zealand rug mer- 
chant, a lady from Australia. There were 
people from all walks of American life, 
many of whom paid their last $2,000 to 
attend. 

Not all of the participants succeeded. 
But so many did become successful and so 
many told me later how I literally chang- 
ed their lives, that I was convinced Suc- 
cess Forces should be available for every- 
body to use. 

NOW AVAILABLE 

I am now making my concept available 
in a hardbound book entitled "Success 
Forces." It contains examples from my 
speeches and the philosophies from my 
seminar that participants paid $2,000 to 
hear. 

A few of the Success Forces you may 
already know and have been subcon- 
sciously following for years. Others, you 
may have been fighting, thinking that 
you would fail when all along you would 
have succeeded. A few of my Success 
Forces require action— the type of action 
that everybody can take and that re- 
quires no special skill. 



This is not a step-by-step book on how 
to get into a business that promises "A 
Lazy Way to Riches," or a way to "Quit 
Your Present Job." It does not matter if 
you are in business nor whether you want 
to work hard, take it easy, or just plain be 
successful. 

TEACH HIM TO FISH 

There's a saying: "You can feed a man 
a fish and he'll eat for a day. But teach a 
man to fish and he'll eat for a lifetime." 
My book will help you for a lifetime. 

I'm not somebody who writes a book on 
how to make a fortune and then makes 
my fortune from the sale of the book. I've 
already made it. Nor am I going to send 
you a cheaply printed thin paperback. 
That's not my style. My book is a 200 
page hardcover volume that I guarantee 
you will both enjoy and benefit from. In 
fact, I will go one step further. After you 
read it, wait one year. If you have not 
noticeably benefited from reading Success 
Forces, return your book to me and I will 
refund your money in full. Success Forces 
must give your life additional meaning 
within one year or your money back. It's 
that simple. This one-year return offer 
applies only to those individuals purchas- 
ing my book via mail order. 

EASY TO ORDER 

I've also made it easy for you to order 
my book. Credit card buyers may call my 
toll-free number below or send your 
check or money order for $9.95 plus $2.00 
postage and handling (Illinois residents 
please add 6% sales tax) payable to: 
Joseph Sugarman, Dept. RA, Two JS&A 
Plaza, Northbrook, Illinois 60062. 

I've built my business and reputation 
on providing solid value to the consumer. 
Success Forces represents my ultimate 
product and my greatest value. Order a 
copy at no obligation, today. 



PRODUCTS 
THAT 
THINK- 

Call TOLL-FREE 800 323-6400 

In Illinois Call (312) 564-7000 

©Joseph Sugarman, 1980 




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Spend less, 
lest more. 



Integrated circuits are very private 
devices. When something goes wrong, they 
just don't work. Which is tough enough when 
part or all of one IC goes bad. But 
often worse, because a single bad 
IC usually means a large, complex system 
that won't function properly. 

Until now, you could spend a lot of money 
and time— and still only be guessing what 
was happening at any point in a logic system. 



settings, no sync, no wait. A switch selects the 
proper logic family. The probes derive their 








' 




LOGIC PROOE U»-t 






i 



Logic Probe LP-1 Captures pulses as fast as 50 nanoseconds, 
to 10MHz Latching memory Bargain-priced at only S50.0G* 

We put troubleshooting at your 
fingertips. Now, there's a quicker, surer, less 
expensive way to get the information you need. 
Our multi-family Logic ProPes. Their LEDs 

light to show you at a glance the 

logic state at any point— and more. 
Catch fast pulses, even store them if you like. 
A flashing light signals pulse trains. And you 
can even approximate the duty cycle of asym- 
metrical waveforms. 

Nothing could be simpler. No complex 



Logic Probe LP- 2. All the basic features of LP-1 , with pulses 
as last as 300 nanoseconds, to 1 5MH; Doesn't have LP-1's 
memory feature but features even lower price: $28.00" 

power from the circuit under test. High input 
impedance prevents circuit loading. And all you 
do is touch the tip to any pin, pad or path for an 
^^ m ~~ instant picture of circuit conditions. 
Laboratory quality. Economy price. 
High speed. High precision. Even memory. 
Our Logic Probes deliver all the performance 
you need for design, development, debugging 
and servicing. Making digital work less of a 
chore, more of a bargain. 




Logic Probe LP- 3. Five times the speed of LP- 1 at less than 
twice the price. Captures pulses as narrow as 10 nanosec- 
onds, to over 50MHz Latching memory. The new value 
standard, at $77.00* 



Smarter tools for testing and design. 

GLOBAL Call toll-free for details 
SPECIALTIES 1 -800-243-6077 

^^" »^^"^^™> "M^^ Durinq business hours 

CORPORATION 

Suggested U S resale Prices, specilicaltons subject to cnange without notice © Copyright 1980 Global Specialties Corporation. 



70 Fulton Terr New Haven CT 06509 (203) 624-3103. 1WX 710-465-1227 

OTHER OFFICES. San Francisco (415) 4214872 Twx 910-372-7992 

iuiooe Phone Saflion-Wiloen 0799-21682 TLX 917477 

Canada Len Fmkler Lid Downsview. Ontario 



CIRCLE S8 ON FREE INFORMATION CARD 




Electronics 

Electronics publishers since 1908 



THE MAGAZINE FOR NEW 
IDEAS IN ELCTRONICS 



OCTOBER 1980 Vol. 51 No. 10 



SPECIAL SECTION 



45 YOUR OWN COMPUTER, Jutes K. Glider 

47 Radio Shack's TRS-80 

51 PET Personal Electronics Transactor 

54 The Apple Computer* 

57 OSI Superboard & Challenger 

59 Heath H89: Kit or Assembled 

61 HereComeaTT 

63 Computers, Computers, Computers 

69 Peripherals and Accessories 

74 Software and Data via Telephone 

78 Computer Languages: The Human Interlace 



BUILD THIS 



87 



92 



SYNTHESIZED FUNCTION GENERATOR 
This is a precision laboratory or test-bench instrument 
capable of accuracy to 0.005%. Use it with logic circuits 
or as an audio or RF signal generator. Gary McClellan 

UNICORN-1 ROBOT 

Part 3. Design and construction of the mobility base 

James A, G Upton, Jr. 



TECHNOLOGY 4 LOOKING AHEAD 

Tomorrow's news today. David Lachenbruch 

8 SATELLITE TV NEWS 

The latest happenings in an exciting new industry. 
Gary H. Arfen 
96 DOT/BAR-GRAPH DISPLAY DRIVERS 

Two fC's that simplify construction of an LED display... 
and the IC's have other uses. too. Michael X. Malda 

108 FLASHER LED APPLICATIONS 

Those LEO'S that blink by themselves can be put to 
many unusual uses. Calvin R. Graf, W5LFM 

110 NEW IDEAS 

A prize-winning application from our readers. 

112 HOBBY CORNER 

Digital panel meters, the easy way. 
Earl "Doc" Savage, K4SDS 

VIDEO 124 SERV| CE CLINIC 

What to do about too much brightness. Jack Darr 

125 SERVICE QUESTIONS 

R-E's Service Editor solves technicians' problems. 

AUDIO 106 R.E.A.L. SOUND LAB TESTS HAFLER MODEL DH-200 

STEREO POWER AMPLIFIER 
David Hafler's new amp rates excellent. Len Feldman 

RADIO 105 PIONEERS OF RADIO: NIKOLA TESLA 

This amazing man opened the door to modern-day 
communications Fred Shunaman 

116 COMMUNICATIONS CORNER 

Using one antenna with several radios. Herb Friedman 

EQUIPMENT 14 International Instrumentation C-Probe II Capacitance Meter 

REPORTS 22 Regency Model M-100 Programmable Scanner 

24 B&K -Precis ion Model 3020 Sweep/Function Generator 

32 Texas Instruments TM990/189 Single-Board Computer 

38 VIZ Model WRS158 Color-Bar Generator 

40 SGM Model BAX-1 Broadband Amplifier 



DEPARTMENTS 



152 Advertising Index 

10 Advertising Sales Offices 

126 Books 

153 Free Information Card 



10 Letters 

128 Market Center 

114 New Lit 

115 New Products 
6 What's News 



ON THE COVER 

A synthesized pulse generator that 
goes from 0.1 Hz to 1 MHz. All CMOS 
design, this device is ideal for putting 
logic circuits through their paces and 
for use as an AF and RF signal genera- 
tor. Synthesizer allows exact selection 
of frequency and guarantees repeat- 
ability. Construction details begin on 
page 87, 




SPECIAL COMPUTER- SECTION covers recent 
developments in the personal computer field. 
Find out what's for you, starting on page 45. 



■ ? 


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Of SCALpjB 

•^VOLWETEwfc 





LED DISPLAYS are showing up in more and 
more designs. Learn how to design your own 
on page 96. 

Rsdio-EtectronlcB, (ISSN 0033-7862) Published monthly 
by Gemsback Publications, Inc.. 200 Park Avenue South, 
New York, NY 10003. Controlled Circulation Postage 
Paid at Concord NH. One-year subscription rate: U.S.A. 
and U.S. possessions, SI 3,00. Canada. $16,00. Other 
countries, $18.00. Single copies $1,25. © 1950 by Gems- 
back Publications, Inc. Alf rights reserved. Pnnted in 
U.S. A, 

Subscription Service: Mail all subscription orders, 
changes, correspondence and Postmaster Notices of 
undelivered copies {Form 3579) to Radio- Electronics 
Subscription Service, Box 252G H Boulder, CO 80322. 

A stamped self-addressed envelope must accompany 
ail submitted manuscripts and/or artwork or photo- 
graphs if their return is desired should they be rejected. 
we d I sc la I m a ny responsibi I i ty for t he loss or damage of 
manuscripts and/or artwork or photographs while in 
our possession or otherwise. 



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As a service to readers. Radio- Electronics publishes available plans or information rotating to newsworthy products, techniques and scientific and technological developments. to 
Because of possible variances In the quality and condition of materials and workmanship used by renders, Radio-Electronics disclaims any responsibility for the safe and proper CD 
functioning Of reader-built projects based upon or from plans or Information published In this magazine, CO 




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Staking a claim: Sony made the unusual move of demon- 
strating a "new product" four to five years before its in- 
troduction when it recently showed a hand-held combina- 
tion video camera and VCR designed to replace the 
super-8 film camera. At press conferences in New York 
and Tokyo, Sony's Chairman, Akio Morita, and its Presi- 
dent, Kazuo Iwama, urged the electronics industry to get 
together on a single standard before introduction to 
avoid a situation similar to the Beta-VHS fiasco. 

The camera-recorder combines a CCD color camera 
with a metal-tape helical-scan VCR in a package weighing 
4.4 pounds, including a rechargeable 9-volt battery. The 
single-chip camera has 570 x 490 picture elements that 
provide a 250-line horizontal resolution, a 3-1 zoom lens 
and through-the-lens viewfinder. The two-head recorder 
uses a cassette resembling a micro audio cassette in 
length and width, holding 8-mm tape, which will record 
for 20 minutes. 

The battery operates for 40 minutes on a charge. For 
playback, Sony showed a "home editor," which accom- 
modates the entire camera (except the battery-pack 
handle) in a special compartment. The editor's output is 
fed directly to a television set for playback or to any home 
VCR (Beta or VHS) for home editing. Morita said that the 
system should sell for under $1,000, cassettes $10 each. 
Sony says its aim is the standardization of cassettes, so 
they may be purchased anywhere in the world, in the 
same manner as super-8 film. 

Sony's competitors were caught off guard by the 
demonstration. Comments from Matsushita, Toshiba, 
and JVC all indicated that they, too, are working on similar 
single-piece units. Eastman Kodak, believed to be pre- 
paring to take the plunge into electronic photography, 
was silent. Now that Sony has gone public with a top- 
secret project that has preoccupied the industry, you can 
expect to see more advance demonstrations of the home- 
movie machine of the future. 

BASF gives up: Germany's BASF has abandoned its plan 
to make its Linear Video Recorder (LVR) in the United 
States, and all plans to produce anywhere the model that 
was first demonstrated as a pre-production prototype a 
year ago have been called off. The LVR plant in Fountain 
Valley, CA, has been closed and put up for sale. Under 
development for at least five years, BASF's LVR was a 
product whose time had passed. The pre-production 
prototype recorder used a rapidly-reversing single-reel 8- 
mm tape with 72 longitudinal tracks. The prototype 
recorder weighed 11 pounds, a remarkable feat three or 
four years ago, but not much lighter than some of today's 
VHS recorders. BASF says it is still working on a 
miniaturized version — perhaps similar to the four-pound 
mockup it displayed privately at last year's Berlin Interna- 
tional Radio & TV Exposition. 

Toshiba's LVR (in this case, standing for Longitudinal 
Video Recorder) has also been postponed, as noted here 
last month. Toshiba's version also uses a single-reel cas- 
sette, this one containing V-t-inch tape with 300 longitudinal 
tracks. The tape doesn't change direction, but the head 
moves from one track to the next after playing, in a 
manner similar to the eight-track audio cassette. Toshiba 



now indicates that LVR will be introduced in two special- 
ized versions before being placed on the general con- 
sumer market. The first will be a random-access data 
recorder, and the second a video recorder capable of 
taping two shows simultaneously on different tracks, with 
a recording time of at least two hours, or one hour per 
show. 

Videodisc competition: With two videodisc players now 
on the market in selected areas, competition is beginning 
to come into play. At presstime, Magnavox's Magnavision 
was officially available in eight U.S. markets (and un- 
officially in some others, as the result of transshipping by 
some dealers) and Pioneer's Laserdisc in four markets. 
Both play the same MCA optical discs. The suggested list 
price of the Magnavision player is $775, of the Pioneer 
$749 (wireless remote random access is a $50 option). 
The competing players meet head-to-head in the Dallas- 
Fort Worth and Minneapolis-St. Paul markets. A quick 
survey of dealers in those areas shows the Magnavision 
selling in most stores there at $695 to $699, the Laserdisc 
at list price. In other Magnavision markets, dealers are 
adhering to the suggested list price. Magna vox says 
there has been no price reduction, indicating that 
"aggressive dealers" are merely meeting local market 
conditions. 

Projection update: General Electric has introduced that 
three-tube projection-TV system forecast in our July 
column. The company seems to have gone out of its way 
to make up for the deficiencies of its single-tube version. 
The new Widescreen 3000, like the old 2000, is a rear- 
projection unit with a 45-inch translucent screen. The 
new version, however, has an extremely bright picture 
with very wide wide-angle viewing — meaning that viewers 
don't have to sit directly in front of the set to see the 
optimum picture. It lists at about $3,500, as compared 
with $2,800 for the earlier version. As reported here, 
Panasonic and Quasar also are selling three-tube rear- 
projection sets, and Sylvan i a plans to enter the market. In 
other projection-TV news, new brighter three-tube front- 
projection sets are expected this fail from Mitsubishi and 
Sony. Kloss Video's Novabeam projection system, the 
least-expensive high-quality three-tube system on the 
market, has been increased from $2,500 to $2,995. 

New sports display: Attendees at this year's All-Star 
Baseball Game at Dodger Stadium in Los Angeles were 
treated to the latest in stadium giant picture displays — the 
premiere of a new Mitsubishi system to replace the old 
light-bulb-type display. Diamond Vision uses 1 x 1, 25-inch 
cathode-ray tubes instead of lightbulbs, in groups of 
three-one for each primary color. The Dodger Stadium 
display measures 20 by 28 feet, is clearly visible in full 
daylight, and will be enlarged next year to 25 by 33 feet. 
Among the claimed advantages are higher resolution, 
better brightness and motion, and longer life for the 
cathode ray tubes as opposed to light-bulbs. 

DAVID LACHENBRUCH 

CONTRIBUTING EDITOR 



NOW! A MINIATURE TELEPHONICS SYSTEM 
EVEN MA BELL DOESN'T MAKE AVAILABLE. 

FINGER 
FONE 

The unique Finger Fone brings you 
advanced solid-state wizardry, with 
total hands free conversation, 
speak and listen without lifting a 
finger. The total communications 
instrument for home and office. 




Imagine you're a design engineer. 
You've just been assigned to come up 
with a smaller, . simpler-to-use, more 
streamlined telephone with basic mem- 
ory that can handle 99% of the ways 
people actually use a phone on a day- 
to-day basis. 

You have a research laboratory with a 
support staff at your disposal. Plus 
access to the latest transistors, memory 
chips, and microprocessors. And you 
are given only one limitation: Keep the 
consumer's cost under $100. 

Now, since you're something of a 
maverick, your mind is not trapped in the 
right way /wrong way syndrome. And 
you were too independent to take that 
job with the Bell System a while back. 
Because you didn't want all your ideas 
to come out "Bell-shaped. " 

THE ANATOMY OF DESIGN 

So you set to work — but not with 
wires, bells and whistles. Because your 
approach is different: You're going to 
discover how people actually use a tele- 
phone today and then design the Instru- 
ment from the outside in, basing your 
conception around real communication 
needs in a way quite unlike anything 
ever before achieved. 

INTRODUCING THE FINGER FONE 

When you're finished, you realize 
you've come up with a minor revolution 
in design! Your new instrument is actu- 
ally a miniature telephone: the entire unit 
measures a scant 2V4" wide, 8V*" long, 
and 2V<" high {at the speaker end), 
scarcely any bigger than the handset on 
an ordinary phone. Your Finger Fone 
has a nearly standard alphanumeric key- 
board plus a couple of special benefits 
we'll get to in a minute. It also has an 
omnidirectional microphone, volume 
selector key, automatically control the 
volume of incoming voices, with four 
LED indicator lamps to display each vol- 
ume level, and even a bright red on-oft 
light. 

What's more, it plugs Into the new 
miniconnector Ma Bell provides for all 
its phones these days — with no addi- 
tional wires for any other power source 
(which make the Finger Fone unlike 
those other multi-wire "speaker-phones" 
that sell for more but do less). 



Finger Fone: modular, sophisticated, smarter than your present 
telephone. Comes with an ivory fascia. 

WHY PICK A PHONE UP 



EVERY TIME IT RINGS? 

Let's face it, your hands are often 
occupied when the phone rings. So to 
answer, you've got to stop at least half of 
what you're doing. With a Finger Fone, 
all you do is reach out and tap the "On" 
key with one finger. And since you 
needn't pick the instrument up, you can 
place it conveniently on a desk, counter, 
or table — or hang it on the wall. 

MORE FINGERTIP CONVENIENCE 

When Finger Fone announces an in- 
coming call with its pleasant electronic 
chirp, tap the "On" key and begin speak- 
ing. It the caller is someone the whole 
family wants to hear, simply tap the 
volume control key and select one of the 
four sound levels and your caller's voice 
will be audible to everyone in the room. 
This benefit is great for the office as 
well, making it possible to replace an 
ordinary telephone, separate speaker- 
phone, and their complicated controls. 

If you wish to speak with complete 
privacy, press the volume control key for 
low level volume. Yes, for strictly private 
calls you'll have to hold Finger Fone up 
to your ear. You won't mind, however, 
because the entire unit is a mere 11 Vi 
ounces, just a featherweight more than 
ordinary telephone handsets. 

YOU HEAR THEM, 
THEY DONT HEAR YOU 

Need to put your caller on "hold" for 
a moment? Easy. Tap "hold" key. All 
five LED indicator lamps will be blinking, 
indicating your caller is on hold. The 
other person won't be able to hear you, 
but you'll be able to hear him or her. 
We recommend you tell people about this 
so they don't make unguarded comments 
they think you can't hear. When you're 
ready to resume your call, simply tap 
"off" key, the LED lights will stop blink- 
ing, and you can continue. 

BUSY SIGNAL? FORGET IT! 

Because Finger Fone automatically 
remembers the most recently dialed 
"busy" number. When you want to call 
that number again, tap the "RE" (Recall) 
key once. Finger Fone dials the number 
for you, as often as needed until you get 
a clear line. 

CIRCLE 39 ON FREE INFORMATION CARD 



WHY WAIT FOR PUSH BUTTON 
DIALING? 

Finger Fone is compatible in areas of 
the country where push-button dialing 
is already in use. But if you live in the 
30% or so of the country where only 
rotary-dial phones can be used, wait no 
longer. Finger Fone automatically con- 
verts from musical tones to rotary-dial 
signals. This way, you can have the 
speed and advantages of push-button 
dialing without waiting for your local 
phone company to install central equip- 
ment. 

NOW AVAILABLE AT INCREDIBLE 
LOW COST 

Finger Fone costs only $79.95 com- 
pared with prices of similar-looking tele- 
phones (but not similar in performance) 
costing $109, $130 or more. Want two? 
Then It's only $74, 95 each. Three? Save 
even more at $69. 95 each. Add a $2. 50 
charge to your total order for insured 
shipping, and if you live in New Jersey, 
include 5% tax. 

MONEY-BACK GUARANTEE 

You can try one or more Finger Fones 
in your own home for 30 days, protected 
by our unconditional money-back guar- 
antee. If you're not satisfied with Finger 
Fone for any reason, simply return it 
(insured) for a full refund, no questions 
asked. Finger Fone is also covered by 
a 1-year parts and labor guarantee. 

To order Finger Fone, call toll-free 
now. We're open 24 hours a day. You 
can charge it on Master Charge, Visa, 
American Express, Carte Blanche or 
Diners. 

800-526-2801 
800-257-7850 

In New Jersey, Call: 800-322-8650 

N.J. residents please add 5% sales tax. 
You can also mail your order with check 
or money order to: 

#"^^ INT ERNATIONAL SALES GROUP 

m]mE3ciH¥ 

W THE IMAGINATION PEOPLE 11 



Dept. RE 10, Lakewood Plaza 
Lakewood, N.J. 08701 



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New console for two-way interactive 
cable TV 

Described as a "major milestone" in the 
evolution of two-way interactive cable tele- 
vision, the GUBE III home computer con- 
sole (known as the Pioneer BT-1300) was 
introduced by Warner Amex Communica- 
tions, Inc., and Pioneer Communications of 
America in May. The BT-1300 is half the 
size of present QUBE consoles; it can 
accommodate up to 110 program chan- 
nels, and has the capacity to provide any 
home service, data information retrieval, or 
video-entertainment programming current- 
ly available, as well as those likely to devel- 
op in the next decade. 




THE NEW QUBE III home console looks like a 
pocket calculator, but it can access up to 110 
video channels. It can support eight numeric 
digits of variable-length data to and from the 
terminal; that enables subscriber* to tie in with 
a wide variety of home service applications. 
(Photo courtesy Warner Amex QUBE.) 

By pressing buttons on the console, sub- 
scribers will be able to interact directly with 
programs they are watching: They can reg- 
ister opinions, vote on issues, participate in 
games, shop from their homes, and take 
educational courses. There are eight nar- 
rowcast channels for education and other 
services, and twelve interactive response 
buttons on the home console. 

Home applications include financial man- 
agement, whereby a subscriber can make 
bank deposits or withdrawals by simply 
punching in a digital code on the console 
that would tell the computer which home 
terminal is requesting a service and that 
the service is banking. The computer will 
check to make certain that all figures are 
correct and a final verification of the trans- 
action will go back to the subscriber. The 
users will also have instant access to mate- 



rial from data-information banks and ser- 
vices such as electronic libraries. Bob Mat- 
sumoto. President of Pioneer Communica- 
tions of America, said: "The unique BT- 
1300 console represents the most ad- 
vanced, sophisticated interactive system 
available in the industry today. There is not 
another system that can approach it in 
terms of performance both now and sever- 
al years hence." 

Latest "schoolboy mystery" 
causes international foul-up 

Unauthorized access to several Canadi- 
an computer systems has been traced 
back to a New York City school whose stu- 
dents range from the fourth to the twelfth 
grades. (The headmaster suggests "It's 
possible that someone outside is using a 
phone that's been traced back to a school 
tine.") 

The Dalton school has a computer that is 
used to teach its students. But the comput- 
er is getting into systems operated by 21 
Canadian business and other organiza- 
tions — systems to which the school does 
not even subscribe. 

In one case, the unauthorized communi- 
cations seized control of the systems used 
by Canada Cement La Farge, and de- 
stroyed some of its data in the process. In 
another, the operation of Scott Hart and 
Associates' computer system was dis- 
rupted. 

All things are possible to a student, some 
teachers of long experience believe, and 
this highly unexpected development could 
be the result of a struggling youth trying to 
solve a routine problem. It Is only slightly 
more probable that some student or staff 
member may have developed a way to 
break security codes previously considered 
invulnerable. The Federal Bureau of Inves- 
tigation, citing a possible scheme to de- 
fraud, obtained a search warrant and 
seized two plastic bags containing comput- 
er printouts and a terminal log sheet; 
results have not been reported. 

New Zenith TV? have 
two non-TV features 

Zenith has taken one step more toward 
making the TV an integral and necessary 
part of the home, with two new features, 
the Space-Phone color TV that doubles as 
a remote-operated extension telephone, 
and the Video Sentinel System, a TV 
receiver, home-surveillance system, and 
door-answering convenience all-in-one. 

The Video Sentinel System consists of a 
12-inch black-and-white TV receiver with 
special circuitry for the video monitor and 
intercom functions, a closed -circuit TV 
camera with stand, and a doorbell intercom 
unit, with connecting cables. 

By pushing a tv button on the top of the 
set, the ordinary program Is brought in. 



Pushing the camera button brings a picture 
from the camera location (front porch, 
back yard, nursery, or elsewhere). The talk 
button permits talking and listening to a 
front door caller. 

The suggested price of the system, with 
all its equipment, is under $400. 

The Zenith Space Phone is a TV set that 
receives incoming telephone calls when the 
set Is connected to an ordinary telephone 
line jack. The viewer answers the call from 
his easy chair with the Space Command 
button on his TV remote control, then uses 
the set as he would a speakerphone. The 
caller is heard through the TV's audio sys- 
tem, and a microphone in the set transmits 
voices in the room to the caller. The Space 
Phone can also be used on outgoing calls, 
after the connection is made on a conven- 
tional telephone. 

FCG reconsidering Magnavox AM 
stereo decision 

The FCC, in a move that did not come as 
much of a surprise, is having second 
thoughts about which AM stereo system it 
will approve. Its original Report and Order, 
as announced in April of this year, was to 
have given the OK to the Magnavox sys- 
tem. 

Radio- Electronics was in the course of 
preparing a report on that system for this 
issue when, at the end of July, the FCC 
announced that, in the process of prepar- 
ing the Report and Order, it had realized 
that it required more information than it 
possessed. Consequently, a Further Notice 
of Proposed Rulemaking will be issued to 
obtain more facts about all the systems 
originally proposed. This means that the 
five contenders for this market— Belar, 
Harris, Kahn. Magnavox and Motorola — 
are all back in the running. 

Sony and Studer agree on 
digital audio recording 

At a press conference held at the recent 
Audio Engineering Society convention in 
Los Angeles, the Sony Corporation and 
Willi Studer, prominent audio equipment 
manufacturer of Switzerland, announced 
that they have reached an agreement to 
support a common format in stationary- 
head digital audio recording. Studer will 
have access to Sony's advanced digital 
tape recorder technology. 

Sony has been conducting its own re- 
search and development in digital audio 
recording and playback. The company at 
present has a full line of digital equipment, 
including pulse-code-modulation (PCM) 
digital audio processors and editing sys- 
tems for professional sound recording. 

Digital recording technology represents 
the best attainable form of sound recording 
and promises to usher in a new era of 
music and audio enjoyment. R-E 



Facts from Fluke on low-cost DMM's 



Our new 4%-digit bench/portables 
You've never seen anything like it. 



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This is the new 8050A from Fluke, 
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The legends on the LCD are 
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dB: You're right. The 8050A 
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Use the "REF Z" button to scroll 
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REL: For relative references in the 
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RE 10/80 



Name 






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City 


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For technical data circle no. *8 



satellite tv neivs 



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Less expensive satellite equipment 

Cheaper satellite private terminals — and more of them — will 
continue to become easier to find. That was the message during 
two recent expositions, both of which underscored the growing 
popularity and interest in backyard earth stations. 

First in Chicago, at the Consumer Electronics Show, small- 
dish antennas made their first formal appearance, with three 
distributors showing off their equipment. The units were in the 
$5,000 and $10,000 range — and the purpose of the Chicago 
display was to interest electronics dealers from around the coun- 
try in selling the devices in their stores. From all indications, the 
companies were successful — and more stores nationwide will 
soon be selling and installing equipment. 

A couple of weeks later in San Jose, California, the semiannu- 
al Satellite Private Terminal Seminar attracted more than 600 
people — and for that group of do-it-yourselfers, the price of 
equipment shown was in the $2,500 range. For the California 
event, nearly three dozen equipment suppliers showed their 
wares, including a number of new and exotic small antennas. At 
the low-end of the scale was a $495 16- pound umbrella antenna 
developed by Bob Luly of San Bernardino, California. The price 
of LNA's also continues to fall, with some units now in the $800 
range. In addition, an 80° parametric amplifier selling for about 
$500 was demonstrated. Sat -Tec, a Rochester NY subsidiary of 
Ramsey Electronics, demonstrated its $995 R2 satellite receiv- 
er, which requires a 1 20° low-noise amplifier, and features con- 
tinuous tuning for all U.S. domestic satellites, Intelsat, and Rus- 
sian Molniya. 

Of the companies showing complete TVRO packages at the 
Consumer Electronics Show, the lowest-price offering was a 
$5,000 set-up jointly presented by Heifer's Antenna Service (23 
Brookside Place, Pleasantville, NY 10570) and American Value 
Inc. (PO Box 96, Rolling Meadows, IL 60008). Heifer's built 
and demonstrated the equipment, which American Value is sell- 
ing. The package has only one LNA and the low price is for a 
10.5-foot dish; with a 12-foot dish, the price rises $500. 

Third Wave Communications (3618 Elizabeth, Ann Arbor, 
MI 48103) a company that takes its name from Alvin Toffler's 
popular new book, uses Microdyne hardware. President Jim 
Cassily is looking forward to the 1990's when he expects that 
12/14 GHz satellites will make the current generation of equip- 
ment obsolete. With that in mind, Third Wave is working with 
technologists to see if current 3-to 5-meter dishes can be con- 
verted into solar satellite collectors for future energy-retrieval 
applications. 

Channel One, Inc. (Willarch Road, Lincoln MA 01773), one 
of the pioneering TVRO distributors, added a new feature to its 
CES display: a fiber-optics cable to carry the satellite feed the 
last 1 ,500 feet from the convention hall parking lot into a video 
exhibit on the display floor. It was the first time that fiber optics 
have been used for such a long drop, and users were pleased 
about picture quality — immune from RF interference, which 
was rampant within the electrified building. 

"SPACE" signing up members 

SPACE, the Society for Private and Commercial Earth Sta- 
tions, held its first formal meeting during the Satellite Private 
Terminal Seminar (see above). It signed up more than 140 
members and elected Stanford University Professor Taylor 
Howard as President. The group's first thrust will be to respond 
to proposed legislation that would prohibit private reception of 



pay TV programming. SPACE opposes any payments for pri- 
vate use of satellite signals and wants assurances that backyard- 
terminal owners will not be denied access to satellite signals. 
However, an informal poll at the SPACE meeting indicated that 
commercial users would be willing to establish a "reasonable 
payment" for programming (such as at apartment complexes). 
SPACE has established three classes of membership: individual 
($25), corporate ($100), and sustaining ($500). The group's 
membership is now about evenly split between manufacturers/ 
suppliers and satellite users (SPACE, 1527 O Street NW, 
Washington, DC 20005.). 

Washington trying to stop unauthorized reception 

With the growing use of private satellite terminals, it was 
inevitable that Washington officials would begin to examine the 
business. In fact, a bill was recently introduced in Congress (HR 
7747) to prohibit "unauthorized interception" of pay-TV pro- 
gramming from satellites and other microwave systems. The 
proposed law would establish penalties, including a $100-per- 
day liability to the program provider and fines of up to $25,000 
and/or one year in jail. Moreover, retransmission of such signals 
for commercial purposes (such as distribution within an apart- 
ment or hotel building) could carry a $1 million fine. Washing- 
ton observers aren't certain how the legislation will fare when — 
or if — it ever comes up for a vote. 

Meanwhile, over at the Federal Communications Commis- 
sion recently, there was a brief discussion of signal piracy. After 
a short examination, the Commission decided it will file a 
"friend of the court" document in a California case involving 
alleged piracy of a microwave pay-TV signal; and at least one 
commissioner is pushing for the FCC to adopt a formal "anti- 
piracy" stance. 

To confuse things a bit more, let's take a look north of the 
border. The Canadian Radio- Television Commission (equiva- 
lent to our FCC) wants to prosecute owners of illegal receivers; 
but at least one leading public official there has issued a state- 
ment: "Hands off the earth stations of northern Ontario." 

Ontario Communications Minister James Snow supported 
the use of TVRO's, especially in outlying areas, because they 
"reduce the isolation" caused by lack of media outlets. 

Around the satellite circuit 

The FCC has formally opened the books on plans and propos- 
als for Direct Broadcasting Satellites in preparation for the 1983 
western hemisphere World Administrative Radio Conference. 
That international meeting will decide what frequencies and 
power are to be allotted for DBS in North and South America; 
so the FCC plans to spend about two years getting ready for that 
session. If you want to file comments or ideas (especially about 
service requirements, orbital positions, or specifications) in the 
preliminary FCC examination (General Docket No. 80-398), 
submit them by October 10, 1980 to the FCC, 1919 M Street 
NW, Washington, DC 20554. 

Japan's "Yuri" experimental direct- broadcasting satellite 
dropped out of service recently when its remaining traveling 
wave tube amplifier ceased functioning. The failure means a 
premature halt to the DBS efforts which had begun last year, 
using one-meter receive antennas. Another Japanese DBS satel- 
lite is already under construction. 

GARY H. ARLEN 
CONTRIBUTING EDITOR 



Yesterday - Remember the first Heath kit 



Single-Sideband Transmitter (1958)? How 
about the Heath kit Multiplex Adapter for 



rTtit iTifiJ» i i Itlil ■ iZl • jf I 



sa ground-breaking 
innovatiomfor its day. Each was 






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compact unit. 



together the best in video techno!* 
to create the sharpest color picture 
ever on a six-foot diagonal screen. 

Heath imagination applied to micro- 
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stores data - and puts it all at your 
fingertips. 

Tomorrow — Tomorrow's brainchild, 
like todays and yesterday's, will combine 
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r. 1 1> m « tf ^tf^tqi ■ *,&■$•) i.i«J.»'.w 



On the drawing boards right now are new 
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They'll be appearing soon in Heathkit 
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VISIT YOUR HEATHKIT STORE 

In the U.S. and Canada visit your 
nearby Heathkit Electronic 
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are displayed, sold and serviced. 
See the white pages of your 
phone book. In the U.S., Heathkit 
Electronic Centers are Units of 
Veritechnology Electronics Corp. 

CIRCLE S3 ON FREE INFORMATION CARD 






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O000OPS . . . AGAIN! 
I think there's an error in the foil pattern 
for the Automotive Voltage Regulator that 
appeared in the June 1980 issue. Pin 1 of 
IC1 does not go directly to ground, as it 
does on the schematic, and it appears to 
me that the circuit will not work without this 
ground. Am I correct? 
JOHN F. BRIDGE 
Worthington, OH 

You're right! (And the same mistake 
appears in the correction on page 72 of the 
July issue.) The solution is to run a very 
Short piece of resistor lead from the pad at 
the pin-1 end of R6 to the ground land 
immediately to its right (on the foil side of 
the hoard). The current production run of 
those hoards does not contain this error 
and purchasers of earlier-production 
boards have been advised of this mistake 
and given the opportunity to exchange 
their "old" boards for the "new" ones- 
Editor. 

RADAR DETECTORS 

First of all, I would like to say that this 
letter reflects only my personal opinion and 
is in no way a policy statement of the 
R.C.M.P. or any other police force for that 
matter. I am a member of the R.C.M.P. in 
Canada and have been for the past five 
years. I am also an electronic audio tech. 

For some time I have been listening to 
the radar and radar detector arguments 
with amusement. Firstly let me speak on 
the radar. 

My writing has been prompted by the 
Feb 80 letter "Radar Detectors vs The 
Law". The writer points out that radar has 
come under severe attack recently— espe- 
cially moving radar— because of situations 
that can cause false readings. I have oper- 
ated radar for the past four years and ! 
agree with the writer on that point. 

However, picking out a speeder in a 
group is quite simple— he is the one whose 
car is going the fastest. As for "batching", 
ghost readings, and large speeding trucks 
behind unsuspecting motorists, the radar 
operator is instructed in the use of the 
radar and is supposed to be able to recog- 
nize those problems and sort them out 
from the true readings. However, modern 
technology has yet to perfect the "idiot 
proof" instrument. Radar is not "idiot 
proof". 

I should mention after watching the flow 
of traffic for five years that an officer can 
judge the speed of a vehicle quite accurate- 
ly, with only the use of his eyes and sense of 
timing. 

Now on the subject of radar detectors. I 
do not feel anything wrong with a person 
owning and operating a radar detector if he 
can afford it and the law permits it in the 
area he lives. But let's be honest with our- 
selves and others, and admit what is usu- 



ally the real reason for radar detector use. 

Many people quote such notable persons 
as mayors, traffic control techs, and elec- 
tronic engineers as saying, "Radar detec- 
tors promote safe driving by making driv- 
ers aware of their speed, thus slowing them 
down, and slower speeds reduce acci- 
dents." 

I cannot dispute that slower speeds re- 
duce accidents, but we will most likely read 
the statistics in the future and see that 
there were few, if any, accidents in the 
vicinity of traffic officers operating radar. 
However, what about the stretch of high- 
way where there is no officer operating 
radar. What will remind drivers of their 
speed there? Hardly anything! 

If we are honest with ourselves we will 
realize that, for most drivers on the road 
owning radar detectors, the primary reason 
is to escape detection when they wish to 
exceed the speed limit. 

For the last several years a device has 
been marketed that satisfies all the claims 
of radar detector owners and distributors. 
It is called cruise control. It helps you keep 
a constant speed and prevents your speed 
from "creeping" when going downhill. It 
also gives you a better average speed over 
a long distance, and any professional driver 
knows that this will save you gas and time 
in the long run. (On a steep downgrade, 
your car can exceed the Cruise Control 
speed setting. So you must still be cau- 
tious. — Editor 

For your own protection, from salespeo- 
ple marketing radar detectors, you should 
know that a detector only detects a radar 
beam when it is present. Modern radar 
units have a microwave lock -off switch that 
allows the operator to turn off the radar 
beam until you are well within its range. 
When the beam hits your car your detector 
will go off. Being so close to the transceiv- 
er, you are also being clocked. Chances are 
you'll get your speeding ticket, lose your 
detector, and get an additional fine for hav- 
ing a detector in your possession. All the 
while a detector distributor is counting your 
hard-earned dollars and waiting for you to 
come back to buy another. There are no 
detectors on the market, nor will there ever 
be, that can detect a radar sef— they only 
detect a radar beam. 

For your own protection, you are better 
off to buy and use a cruise control. Howev- 
er, if you wish to use a detector, make sure 
that your State or Provincial laws allow it or 
you could lose your investment. Lastly, 
don't use your detector so that you can 
speed undetected. With the widespread 
use of microwave lock-off switches, and 
officer-awareness of detector operation, 
the only people making money will be the 
State or Provincial traffic boards and the 
radar detector distributors. 
R. BROWN, Cst. 
St. Albert, Alberta, Canada 



Radio 
Electronics 



« 



Hugo Gernsback (1684-1967) founder 

M. Harvey Gernsback, editor-in-chief 

Larry Sleekier, CET, publisher 

Arthur Kleiman, managing editor 

Josef Bernard, K2HUF, technical editor 

Jack Darr, CET service editor 

Leonard Feldman 
contributing high-fidelity editor 

Karl Savon, semiconductor editor 

Herb Freidman, communications editor 

David Lachenbruch, contributing editor 

Earl "Doc" Savage, K4SDS, hobby editor 

Ruby Yee, production manager 

Robert A. W. Lowndes, production 
associate 

Marie J. Slolfi, production assistant 

Gabriels Margules, circulation director 

Arline R. Fish man, 
advertising coordinator 

Cover photo by Robert Lewis 

Radio-Electronics is indexed in Applied 
Science & Technology Index and Readers 
Guide to Periodical Literature. 



Gernsback Publications, Inc. 
200 Park Ave. S., New York, MY 10003 
President: M. Harvey Gernsback 
Vice President: Larry Sleekier 
Secretary /Treasurer: Carol A, Gernsback 

ADVERTISING SALES 212-777-6400 

Larry Steckler 
Publisher 

EAST 

Stanley Levitan 
Radio-Electronics 
200 Park Ave. South 
New York. NY 10003 
212-777-6400 

MIDW6ST/Texas/Arkansa»/Okla. 

Ralph Bergen 

The Ralph Bergen Co. 

540 Frontage Road— Suite 361-A 

Norihfield, Illinois 60093 

312-446-1444 

PACIFIC COAST 

Mountain States 

Jay Eisenberg 

J.E. Publishers Representative Co., 

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Los Angeles, CA 90069 

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San Francisco, CA 94124 

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60 East 42nd Street 

New York, N.Y. 10017 

212-490-1021 





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International 

Instrumentation C-Probe II 
Capacitance Meter 




CIRCLE 101 ON FREE INFORMATION CARD 
WHEN ONE CONSIDERS THE MULTITUDE OF CA- 

pacitance meters on the market these days, it's 
no wonder lhal ihe prospective purchaser may 
have a difficult time in selecting one. Since the 
published specifications of most units will 
offer accuracies and ranges in excess of ihe 
needs of most service technicians and experi- 
menters, ihe only major decision to be acted 
upon could be ihe monetary value of the vari- 



ous pieces of equipment. If inflation has made 
your wallet look thinner and thinner lately, 
then you may wish to consider the least expen- 
sive unil that will meet your needs and offer 
you Ihe best value for your dollar. That conclu- 
sion will quickly narrow the field down to but a 
few prospects. 

Among those prospects you wilt discover 
one unit thai offers much of what the more 
expensive meters offer but at a fraction of the 
price. The C-Probe II, manufactured by Inter- 
national Instrumentation, Inc., Box 3751, 
Thousand Oaks, CA 91359, is able to meet 
those rigid requirements, while keeping the 
price low, by separating the display device 
from the actual meter. In fact, you make use of 
a standard digital frequency counter as the 
readout for ihe i ester. The company is proud lo 
explain that if you do not now own a frequency 
counter, the low cost or the C-Probe II will 
allow you to purchase good 7-digit (30 ml-Iz) 
counter and the C-Probe 11 for less lhan the 
cost of many capacitance meters alone. 

In use, the compact C-Probe II can be oper- 
ated on its own self-contained rectangular 9- 
volt battery or from the power line by using a 
standard charger/eliminator unit that can be 



plugged into the rear of the C-Probe's case. 
Other power sources may also be used and can 
vary between 6.5 and 16 volts. The circuit uses 
a 78 LOS as an on-board voltage regulator lo 
compensate for the wide range of supply volt- 
ages. The AC adaptor connects lo the battery 
(electrically) through a small LED (light 
Emitting Diode) mounted near the charger 
input jack. That LED glows when in the charg- 
ing stale. A bright glow indicates the battery 
condition as low. As Ihe battery becomes more 
fully charged, the glow diminishes. Of course, 
the AC adaptor must be connected lo the line 
and lo the C-Probe II for the foregoing indica- 
tions to be possible. An optional nickel-cadmi- 
um battery makes an ideal power source for 
this tester. 

Since the accuracy of any piece of test gear 
is no belter lhan the calibration of the unil, this 
little unit has a unique method of assuring the 
calibration accuracy. Inside the C-Probe II is a 
lest point that is derived from the timebase 
crystal operating at 3.579545 MHz. If your 
frequency counter and the C-Probe II both 
agree, and you read 3.579545 MHz, then the 
accuracy of the measurements will be within 
continued on page 20 




4BG20 SUBURBAN 

One of many RCA 

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For full information, see your 
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A DMM SO UNIQUE ... SO VERSATILE . . . 
SO SUPERIOR WE WERE TEMPTED TO 
CALL IT SOMETHING ELSE 

We believe the MX333, with the VARI-PITCH™ and LOGI-TRAK™ 
'unctions, to be the greatest time saving tool in electronics today. It 
ias all the functions, ranges and accuracy you expect from the best 
along with the two additional features which will save enormous 
amounts of troubleshooting time. And the MX333's 202 range gives 
/ou 10 milllohm resolution for those critical low resistance tests. 
Both MX series DMM's have 0.1% basic accuracy plus a 10A range, 
3lus the intelligent case styling that has the size of a hand held, but 
the shape of a better idea. With either unit you get more performance 
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VARI-PITCH 

Not just a beep. ..not just instant ohms. MX333's 
VARI-PITCH audible tone changes frequency propor- 
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by earl The higher the pitch, the higherthe reading. No 
need to take your eyes off the probe or wait for a read- 
out to settle. VARI-PITCH responds Instantly, propor- 
tionally and accurately in all voltage, current, 
resistance and diode test ranges. It even provides 
analog-like audible response to variations for quick 
and easy adjustments and nulling. 

LOGI-TRAK (5 nsec fast} 
Combines the features of a high performance 
logic probe and voltmeter in one convenient function. 
Use any standard 10:1 high frequency scope probe to 
find high and low logic levels and positive or negative 
pulses as narrow as 5 nsec without taking your eyes off 
the circuit I The VARI-PITCH output tells ft all. And, un- 
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UNIVERSAL SIZE AND SHAPE 

MX333 and MX331 are the first digital multimeters 
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No matter how you use a multimeter; In your 
hand, clipped to your belt or on a shelf, no other DMM 
is as convenient as the Hickok MX333 or MX331 ! And, 
with VARI-PITCH, MX333 is really out of sight in 
performance. 

For an exciting demonstration contact your nearby 
Hickok distributor. For the name of your nearest 
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MX333 
$235.00 



MX331 
$179.00 




HE HICKOK ELECTRICAL INSTRUMENT CO. 
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(21BJ 541-8060 . TWX: 810-421-0386 



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Get A GNOME 

the original micro-synthesizer 

Every day more people discover that PAIA's 
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John Simonton's time-proven design 
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and VCF in a low cost, easy to use package. 
Use alone with it's built in ribbon controller or 
modify to use with guitar, electronic piano, 
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The perfect introduction to electronic music 
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EQUIPMENT REPORTS 

continued from page 14 



the tolerances specified by International In- 
strumentation, Inc. If you don't care to "mess 
up" the timebase in thq counter, or you're sure 
it is accurate, then just adjust the trimmer 
capacitor in the C-Probe II to your counter. 
Even if your counter is out of calibration, so 
long as both are reading correctly with each 
other, it will operate just fine. 

The front panel of the meter contains three 
pushbutton switches that provide selection of 
all functions. The left-most switch is the on/ 
off switch, the center switch selects the ilF or 
pF range, and the third switch offers a ten- 
times increase in resolution to the displayed 
value. In addition, a BNC-type output jack is 
located on the front panel. 

The capacitor to be tested is inserted into a 
universal type of spring-loaded connector on 
the top of the case. That unusual connector 
will accommodate test leads and wires up to 12 
gauge. The placement of the input jacks was 
chosen to keep the test capacitor as far 
removed from the front-panel switches as pos- 
sible, to lessen the effects of the hands on the 
test sample. The lead connected to the capaci- 
tor to be tested is merely inserted into the hole 
provided when the lever on the connector is 
pressed. Releasing the lever clamps the lead 
securely in the input jack. 

The C- Probe II is said to operate directly 
with counters made by B& K-Precision, CSC, 
Dana, Data Precision, Davis, Fluke, Heathkil, 
HP, Leader, NLS, Phillips, Polypak, Radio- 
Shack, Sabtronics, Sencore, Simpson, Tek- 
tronix, or any other counter having regular 
repeating gate times of . 1 , 1 , or 10 seconds. We 



didn't check all of the above, but we did oper- 
ate the C-Probe II with a B&K-Precision and a 
homebrewed unit. Both operated as specified. 
To accommodate various gate times used by 
counters, the C-Probe II has an internal adjust- 
ment fjumpcr) that can be changed to match 
your particular counter. Not all counters on 
the market can be used with the C-Probe II. 
The Hickok series which count for .1 or 1 sec- 
ond and then perform housekeeping functions 
for 30 vS before repeating the count cycle is 
said to be one of the few standard frequency 
counters found that cannot be used with the 
C-Probe II. It would be advisable for you to 
check your counter's duty cycle before order- 
ing the C-Probe II. 

The C-Probe II emits a pulse train which 
contains a number of pulses per gate time that 
is directly related to the value of the capacitor 
being tested. Just as an example, using a count- 
er that operates with a 1 -second gate interval, 
the C-Probe II will emit 68 pulses per second 
when the test sample inserted in the input 
jacks is a ,0682 nF. capacitor and the pushbut- 
tons arc adjusted to the tiV range and the X i 
multiplier is selected. The counter will display 
.068 — the value of the capacitor as a direct 
readout. Pressing the resolution button will 
now show the resolution in the X 10 range by 
causing the C-Probe II to emit 682 pulses- 
per-gate interval with the resulting readout of 
.682. In that position it is necessary to shift the 
decimal one place to the left mentally, showing 
an actual reading of .0682 ^F. 

During the testing of our C-Probe II, we 

made use of a few calibration capacitors with 

the following results. A 56 pF unit measured 

56 in the X 1 resolution while it checked as 

continued on page 22 



LEARN ELECTRONICS THE EASY WAY! 



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CIRCLE 42 ON FREE INFORMATION CARD 



21 



EQUIPMENT REPORTS 

continued from page 20 



55.5pF when placed in the X10 mode. A 1.5 
fiF, 20% unit measured 1.48fiF in the direct 
mode and indicated a value of 1. 4884^ F in the 
X10 resolution range. A .33 pF capacitor 
checked out to be .334 directly and at a resolu- 
tion of X10, it indicated .3336uF. 

After using this little unit, measuring only 
2.5 X 4 X 5 inches, it can be said that it 
should provide the service technician and seri- 
ous experimenter with all the resolution 
needed in the shop or lab. Total weight (in- 
cluding the battery) is just 6.5 ounces. Accord- 
ing to International's manual, the accuracy is 
stated simply as ,25% of the capacitor value in 
the pF range and ,5% of the capacitance value 
in the ^F range. In fact, the company claims 



that when one reads the fine print of some 
competitive testers, the C-Prcbe II really turns 
out to be more accurate. The C-Probe II has a 
suggested retail price of $79.95. R-E 

Regency Model M-100 
Programmable Scanner 

FEATURING A MUCH SMALLER FRONT-PANEL 

profile than its predecessors, the Regency 
Model M-100 programmable scanner offers 
flexibility and operational simplicity. 

The M-100 memory includes ten channel 
capacity, indicated by a bright fluorescent dis- 
play. Two brightness levels are switch-selecta- 
ble, or the display may be switched off entirely 
with the radio still operating. 

The display indicates channel numbers 



ADVANCE is Proud to Introduce the WESTON 
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functions not previously available from 
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checking and testing. An audio signal 
response guides the operator in testing. 
An audio signal response guides the 
operator in testing and permits full con- 
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answers to quick, sure and accurate 
testing. 

SPECIFICATIONS 

DC VOLTAGE 



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Weight: 1 lb. Dimensions: 7.5 in. x 3.4 in. x 19 in. 

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The Roadrunner ADMM Features 

• Six Functions 

• 29 Ranges 

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• Color coded easy-to-read front panel 

and pushbuttons 

• 0.5" LCD Display 

• Rugged Case tor "Field Use" 

• RFI Shielded 



THE TEST EQUIPMENT SPECIALISTS -!S- 

TOLL FREE HOT LINE *«im»«#*jw "* 

800-223-0474 ADVANCE—^ 



54 W€ST4W>STR£E1 Nfcrt YORK N Y 10036 2\3- 057-2224 




CIRCLE 102 ON FREE INFORMATION CARD 

while in scan mode as well as received frequen- 
cy when a signal is being monitored. Other 
characters on the readout show loss of power, 
scan delay, individual channel lockout, and 
search mode. 

A priority function may be selected so that 
the listener will be sure not to miss an impor- 
tant transmission. Conventionally enough, 
Channel I will seize control of the receiver 
regardless of mode should the frequency be- 
come active (assuming the priority function is 
activated). 

Tuning-frequency ranges include: 30 to 50 
MHz, 144 to 174 MHz, and 440 to 512 MHz. 
Sensitivity is specified as 0.25 >»V on low band, 
and 0.45 nV on the high band and UHF. All 
sensitivity figures arc measured for 12-dB 
SI NAD (SYgnal + /Voise And distortion) at 
tuneup. 

Scanning rate is a rapid 15 channels-per- 
second; audio output is 2 watts — entirely ade- 
quate for noisy environments such as in mobile 
applications. 

The physical size of the M-100 is a compact 
y/t wide X 2'A high X 9'/. inches deep. 
Weight is V/t pounds. 

Although the top-mounted internal speaker 
is ideal for home use, some volume loss may be 
expected in certain mobile mounting situa- 
tions; adequate reserve volume should well 
make up for any decrease in acoustic sound 
level. A mobile mounting bracket and DC cord 
are supplied for mobile use, as well as the AC 
cord for fixed installation. 

Dual power cords (supplied) enable the 
receiver to be used with 1 10 to 130 VAC at 18 
watts RMS, or 11.5 to 15 VDC at 10 watts 
maximum. 

One innovative feature of the M-100 is a 
beep tone that signals every time the touch- 
entry key pad is pressed. This assures the user 
that his command has registered. 

The keyboard is of the pressure-pad variety, 
so the beep is reassuring since there is no 
accompanying "snap" feel to the command 
when the key is depressed. 

Our field test 

We selected a unit at random from a dealer's 
shelf to perform our evaluation of the M-100. 
We were impressed by the functional styling as 
well as cosmetic appearance of the receiver. 
The keyboard simplicity was a welcome relief 
after sampling other high-technology pro- 
grammables. Needless to say, not everyone 
needs the sophistication offered in the more 
expensive scanners, and the M-100 helps to fill 
that void. Low-band sensitivity was as good as 
that found in the more expensive program- 
mable to which it was compared. The high 
band was nearly as sensitive, and at UHF the 
performance was only slightly less than that of 
the comparison receiver. 

continued on page 24 



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EQUIPMENT REPORTS 

continued from page 22 



We would deduce sensitivity of the M-100 
to be perfectly adequate for metropolitan lis- 
tening purposes. 

Audio quality was excellent — the unit uses a 
voice-shaped passband for maximum intelligi- 
bility. Audio level was certainly adequate for 
nearly any imaginable application. Squelch 
threshold was tight, allowing response to the 
weakest recoverable signals. 

Our unit had two malfunctions: occasional 
key bounce (double integer-entry from one key 
press) and incorrect low-band search range 
(wouldn't search what we programmed). We 
judged these malfunctions to be a fault in that 
particular microprocessor IC and not a prob- 
lem with the basic receiver design. 

The fluorescent display was adequate for 
bright room lighting; although the M-100 was 
not tested in a mobile installation, we would 
not expect any problems in viewing the display 
except in direct sunlight. 

As with earlier Touch products from Regen- 
cy, a special routine allows the M-100 to be 
programmed to search and scan outside of its 
normal frequency range. Some alignment will 
be required for great excursions away from the 
frequency ranges for which the scanner comes 
preset from the factory. 

We were favorably impressed with the M- 
100. Its styling, ease of programming, and 
bright display are certainly important improve- 
ments over earlier models. The Regency M- 
100 programmable scanner sells for $299. It is 
manufactured by: Regency Electronics, Incor- 
porated, 7707 Records Street, Indianapolis, 
IN 46226. 



B&K-Precision Model 3020 
Sweep/Function Generator 




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THE B&K-PRECISION CO.. A DIVISION OF DYNA- 

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continued on page 26 



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EQUIPMENT REPORTS 

continued from page 24 

correct bias level, positive or negative. Since 
this is a voltage-controlled circuit, it can also 
be made to sweep any given band of frequen- 
cies by feeding a ramp, sawtooth or sinewave 
voltage into the GCV jack (Generator Control 
Koltage). 

Sweep can be done with either the internal 
or external control voltage. Scope setup for 
display of frequency response is simple. The 
control voltage (internal) is brought out to the 
GCV out jack, and this can be used for the 
horizontal deflection of the scope. Linear or 
logarithmic sweep can be used, by pushing the 
switch button, Sweepwidth is variable up to a 
1 000: 1 frequency ratio. One continuous sweep 
can cover the entire audio frequency band 
from 20 Hz to 20 kHz, The sweep is flat; bet- 
ter than 0.3 dB up to 2.0 MHz, with sinewaves. 
Any of the three waveforms can be used in the 
sweep mode, but the sinewave is more or less of 
a standard. 

Tone-bursts are also getting very popular for 
some tests, and necessary for others. In this 
mode, an external signal gates the output into 
alternate on-off periods. Any frequency or 
waveform can be used, and the on-off ratio can 
be adjusted. Special circuitry makes the bursts 
of signal start with an even half-cycle, either 
the negative or positive. This makes locking on 
a scope much easier, and also eliminates tran- 
sients and odd harmonic components that 
might cause problems. 

Using an external AC modulating signal, 
you can generate an AM signal at any modula- 
tion percentage. The modulation is set by a 
control on the panel. Only 1 .5 volts of signal is 
needed to get full 100% modulation. The 3020 
can produce a full double-sideband signal, with 
any amount of carrier-suppression. The carrier 
suppression is set by a front panel control. You 
can kill the carrier entirely and see only the 
sidebands. 

A variable-symmetry control is provided. 
This control can make a triangle into a saw- 
tooth or ramp, adjust a squarewave to make 
positive or negative going pulses of any width, 
or make a "slewed sinewave" which is a really 
weird waveform! Frequency of pulses, ramps, 
etc. is controlled by the main tuning dial and 
the multipliers. 

You can make tone-bursts by using an exter- 
nal gating signal. The oscillator frequency can 
also be controlled by a DC voltage. Feeding an 
AC voltage in here will give you frequency 
modulation. A ramp voltage here sweeps the 
frequency over any desired range. Maximum 
voltage needed for full-range sweep is 10 
volts. 

All outputs are 50 ohms. The amplitude of 
the output is controlled over a range of 0-10 
volts peak-to-peak into 50 ohms. There is a 
variable attenuator with a range of to —20 
dB, and three step attenuators, — 10 dB, —10 
dB and —20 dB; this gives you a total of up to 
— 60 dB of attenuation if needed. 

Controls are simple, plainly marked and 
easy to use. There are ten control knobs on the 
front panel that will give you any of the out- 
puts you need. The most-often used outputs 
are controlled from the front, with jacks for 
the generator control voltage output, control 
voltage input, a TTL output at a fixed ampli- 
tude (frequency set by main dial) the AM IN 
jack for external modulation, and the gate in 
jack for external control of tone bursts, on the 
rear panel. All of these are "phono" jacks; the 
continued on page 28 



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EQUIPMENT REPORTS 

continued from page 26 



main 50-ohm output on the front panel is a 
BNC There are ten pushbutton switches on 
the front panel. These control the waveform 
selection, attenuation, and the other functions, 
like linear or log output, cw/am, normal/ 
inverted (for reversing polarity of pulses if 
needed), and the external-internal control 
switch. All ten of these controls arc push-on, 
push-off types. 

All of this comes in a small box only three 
inches high and less than a foot wide. All of the 
controls are "man-sized" and spaced so they're 
easy to get at. Frequency is controlled by a 
variable dial calibrated from 0.2 to 2.0, and a 
seven -step multiplier switch, from X 1 to 
X1000. For uses needing a very precise fre- 
quency, a counter can be used. Normal fre- 
quency accuracy is given as ± 5% of full-scale 
reading. 

Let's look at just a few of the things you can 
do with this instrument, previously either very 
difficult or darn near impossible. We won't 
have space to cover them all. You can sweep- 
align the IF stages of any AM radio. You can 
sweep-align the AM broadcast band, including 
RF stages, etc. Discriminators on FM commu- 
nications receivers with a 455-kHz 2nd IF can 
be aligned. Digital logic circuits of all kinds 
can be checked out. 

You can test tone-burst decoders at any fre- 
quency. In these, a given frequency must be 
received for specific lengths of time to make it 
work. (2250 Hz for 120 milliseconds, etc.). 
The frequency can be set accurately with a 
counter and the burst-length set up quickly on 
the scope. 

Here's the one that impressed me. With the 
model 3020, you can check the modulation- 
limiteronany CB radio in a matter of seconds. 
Just feed in a tone burst at any frequency in 
the set's audio range. Display the input signal 
on the top trace of a dual-trace scope. Feed the 
limiter output to the lower trace. Set the dura- 
tion of the burst so that it is slightly longer 
than the specified attack time of the circuit. 
(Attack time: time between the arrival of the 
signal and when the full compression is effec- 
tive.) This is very easy to see on a calibrated 
scope. You can NOT do this with a continuous 
lone signal. Any frequency within the audio 
band can be used. 

You can check everything in audio circuitry; 
amplifiers for frequency response, linearity, 
flatness, clipping, you name it. Speaker sys- 
tems can be tested for frequency response, and 
the impedance of the speaker or network found 
quite easily. For clipping tests, there is nothing 
that can beat a triangle wave. Even the slight- 
est tendency to clip will show up by the "blunt- 
ing" of the sharp peaks. 

I would also like to hand the writers of the 
instruction manual a large bouquet! It's 68 
pages long, and covers a great many specialized 
tests in great detail. Every detail is shown, 
including illustrations of exactly how the 
equipment is hooked up, and what the output 
should look like. No room to list them all, but 
this is a very good handbook on the uses of 
such a versatile instrument. It's one of the best 
instrument-operating manuals that I've ever 
run across, and I've seen quite a few. This is 
quite a lot of instrument for a modest price, 
and one that should make servicing a lot easier; 
we can all use something like that: The B&K- 
Precision mode! 3020 has a suggested retail 
price of S350. R-E 

more reports on page 32 




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ABOUT THE AUTHOR 
Robert C. Genn is the Director of Engineer- 
ing at Columbia College in Los Angeles, 
and President of the Genn Technical Insti- 
tute. He has been involved in the electron- 
ics field for more than 20 years as a Field 
Engineer, Director of Engineering and 
Electronics, technician and instructor. Mr. 
Genn is certified by the California Institute 
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bleshoot, service and repair microwave 
systems. 



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Please enroll me in the Electronics Book Service on a [rial basis. As my inlroductory selection under 

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Whether you need a test instru- 
ment for electronics service 
work, manufacturing and design, 
or serious hobby applications, 
Heath/Zenith instruments are 
a good choice. The selection 
offered here is just part of our 
total instrument line. Order 
TOLL FREE 800-253-0570. 



O 

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o 

5 



LU 
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3 



NEW 



New 10 Hz-225 MHz 
Frequency Counter 




*159 



05 



• 10 iii V typical sensitivity 

• Single input gives entire range 

• Crystal- controlled time base 

• 0.1,1.0 second dual time gates 

• Full voltage protection 

• Easy- to- read S-Diglt display 
•3.38"Hx7.25'Wx9.0"D 

SM-2410 159.95 

(SZ.30 shipping & handling) 

SMA-Z400-1, Antenna 9.95 

($1,60 shipping &. handling) 






New 5 Hz-512 MHz 
Frequency Counter 




s 299 



• Ideal for 2-way DHF work 

• Ovenized, high-stability, 
crystal time base 

• 8-Digit resolution 

• 10 mV typical sensitivity 

• .01, .1, 1, 10 second gate limes 
to fit your needs 

• Trigger level control 

• Frequency ratio function 

• Period function 

• 4-25"HxlO.O"Wxl3.0'D 

SM-2420 

(S2.75 shipping & handling) 

SMA-2400-1, Antenna 9.95 

{$1.60 shipping & handling) 



.299.95 



Hand-held Multimeter gives D.1% accuracy 

n29 95 

• Measure voltage, cur re tit, resistance 

• Easy-to-read Liquid Crystal Display 

• Five DC voltage ranges - ZOOmV-lOOOV 

• Five AC voltage ranges — 200mV-750Vrnis 

• Four DC current ranges — 2mA -2000 mA 

• Four AC current ranges — 2 mA -2000 mA 

• Six resistance ranges — 200 0-20 Mfl 

• Uses one 9V battery or 120/24 VAC 
•2.0"Hx3.5"Wx7.S"D 

SM-221S 129,95 

($1.75 shipping &. handlingl 

IMA-2215-1 Leather Carrying Case .. 14.95 

($1.60 shipping &, handlingl 

PS-2350 120VAC Battery Eliminator . . 4.95 

($1.60 shipping &. handling) 

PS-2450 240VAC Battery Eliminator . . 14.95 

I $1.60 shipping &, handling) 




New Hand-held 
512 MHz Counter 




^-7995 

• rasy-to-read 7 -digit display 

• 10 mV typical sensitivity 

• Includes nickel-cadmium batteries 

• AC or battery operation 

• .1 second and 1 second time gates 
with automatic decimal point 
placement 

• Leading zero blanking 

• Crystal-controlled lime base 

• Full voltage protection 

• 2.0" H x 3.38" Wx 8.25" D 

SM-2400 179.95 

($1.90 shipping & handling) 
PS-2404 120V Battery Eliminator/ 

Charger (required) 4.95 

($1.60 shipping &, handling) 
PS-2405 240V Battery Eliminator/ 

Charger (required) 12.95 

($1.60 shipping & handling) 
SMA-2400-1 Telescopic 

Antenna 9,95 

($1.60 shipping &. handlingl 



30 



professional quality^ excellent value 



General-purpose 
Power Supply 




$ 210 



00 



• Supplies B+,C- and filament 
voltage ■ 

• 0-400 VDC output at 0-100 mA 
continuous (125 mA intermittent) 

• Output variation less than 1% from 
no load to full load for 100-400VDC 

• Ripple less than 10 mVrms 

• Output impedance 10 I I from 
DC-1 MHz 

• C- Voltage to -100 VDC at 1mA 

■ Filament voltage 6.3 VAC at 4 amp. 

• 5.5"Hxl3.38"Wxll.25"D 



SP-2717 

154.40 shipping &, handling) 



.210.00 



IH-Power Supply 




185 



• Fixed 5 VDC at 1.5A and two contin- 
uously-adjustable 0-20 VDC at 500mA 

• Interconnect outputs in any 
combination 

■ Clutch-coupled Z0 VDC supplies for 
dual-tracking operation 

• All outputs short-circuit proof 

■ Ripple and noise less than S mVrms 

• Load or live regulation provides 
less than 0.1% 120 mV'l variation on 
20V supplies and less than 2% 
variation on 5V supply 

• 4.5" Hi 10.75" Wx 9.0" D 

SP-2718 185.00 

($3.15 shipping &. handling) 



Dual-trace DC-10 MHz 
Oscilloscope 



$ 650 



00 



• Two vertical input channels with 
10 mV/cm sensitivity 

• U-step attenuator for lOmV/cm 
to 20V/cm deflection factors 

• 19-step horizontal time base from 
0.2 sec/cm to u.B usec/cm 

• Vertical accuracy within 3% 

• XS horizontal expansion 

• Calibrated IV peak-to -peak square 
wave signal 

• 35 ns vertical rise time 

• Automatic triggering 

• 120/240 VAC, switch -selectable 

• 6.9" H x 12.9" W x 19.3 " D 

SO-4550 650.00 

{$5.50 shipping &. handling) 




Sine- square wave 
Audio Generator 




$ 185 



00 



• 1 Hz-100 kHz frequency range 

• 0.003-10 Vrms sine wave output 
(lOkHload) 

• 0.003-1 V sine wave output 

teoonioad) 

• Meter calibrated in volts and dB 

• -62 to +22 dB ranges 

• 0.1-10 V square wave output 
12000 a load) 

• 50 nanosecond risetime 

• 5.13 " H x 13 .25 " W X 7.0" D 



SG-S21S 

($2.85 shipping &, handling) 



.185.00 



Combination xl, -v hi 
Scope Probe 



s 29 



95 




• Switch-selectable xl and xlO atten- 
uation at probe tip 

• Center (ground) switch position 
allows quick zero level check 

• DC to 15 MHz (xl) and DC to 80 MHz 
(xlO) bandwidths 

• 4,0 nS (xlO) rise time 

• Insulating tip, BNC tip adapter, 
IC tip, insulated compensation 
capacitor adjustment tool, vinyl case 

PKW-105 29.95 

(SI. 60 shipping & handling) 



Order TOLL-FREE: 
800-353-0570 

8:00 AM to 8:00 PM Eastern Time M-F. Sorry, toll-free service not 
available in Alaska. Hawaii or Michigan. Call 616-982-3411. 24 hours 
a day. seven days a week. TLX: 72-9421 



To receive your order faster, charge it! 

Use your Visa, MasterCard or Hcalh Revolving Charge. 

Please have your card or account number handy when you call. 

charg-Q-kit 



HEATH 



■KITH 



Instruments 




For information on other Heath/Zenith Instruments ivrite: 
Dcpt. 020-708, Benton Harbor, MI 49022 

GX-3B3 



61 Service locations 
throughout the United 
States and Canada 

HeulhfcjE Electronic Centers 
in the U.S * and Canada are 
listed \v\ phone directory 
white pages. 
"Units of Verf technology 
Electronics Curpo ration. 




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31 



EQUIPMENT REPORTS 

continued from page 28 



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Texas Instruments 
TM990/189 Single-Board 
Computer 

THIS S [ NGLE- BOARD M [C ROCOMPUTER IS A COM ■ 

plete system that includes ROM, RAM, 
input and output devices, and uses the 
TMS9980 microprocessor. It is one of the 
most sophisticated of "learning modules" be- 
cause of an unusually comprehensive operating 
system that includes the Unibug monitor and a 
line- by-line assembler. A 45-key calculator- 
like terminal is the primary input/output 
device. A piezoelectric speaker and four LED's 
that are wired to the lower four bits of the user 




CIRCLE 104 ON FREE INFORMATION CARD 

I/O port are additional on-board output indi- 
cators. 

Besides the full complement of firmware 
and versatile alphanumeric terminal the 



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50 CMOS IC 
PROJECTS 
$2.95 

A fascinating col- 
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RADIO CIR- 
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Describes IC's and 
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28 TESTER 

TRANSISTOR 

PROJECTS 

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PROJECTS IN 
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Includes a number of 
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32 



ORDER FORM. — 

n CASH NOW 

tve checked of) three books that I want to buy. I've included payment for two ot them at the full list 

price. I understand the third book is FREE. 

n ST 5 for a 19% discount 

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many books as I want and deduct 15% from the list price. 

P $29 for a 20% discount 

rve checked off the free book and have enclosed my $25 membership fee. 1 understand that this fee 

makes me a member of your book club for one year and that during that time I can order as many 

books as I want and deduct 20% from the list price. 1 further understand that I can use my $25 

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Signature 



City S 

Title 

B50 CMOS Projects S2.95 
Handbook of tc Audio 
Construction $2.95 
H Radio Circuits Using IC's 53.50 
~ 28 Tested Transistor Projects S2.95 

Projects In Opto- Electronics S3. 90 
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MAIL TO: 
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TECHNOLOGY TODAY 

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TM990J1S9 University Module is supported 
by over 800 pages of documentation. Two 
thick books are part of the package: one a 
user's guide and the other a microprocessor 
text intended to be used in combination with 
the computer for a university course. Very few 
instructional systems give you the same sense 
of confidence imparted by the University 
Module. Virtually every question can be an- 
swered by referring to the text, tables or sche- 
matics. Data sheets describe the EPROM, 
RAM, ROM, the TMS9901 programmable 
systems interface (PSI), the TMS9902 asyn- 
chronous communications controller and the 
TMS9980 microprocessor which are either 
part of the system or can be added as options. 

Emphasis is placed on the memory-to-mem- 
ory architecture that, when skillfully applied, 
gives fast computation and efficient memory- 
space use. There is no accumulator as such in 
this microprocessor family. When adding or 
performing arithmetic or logical functions, two 
words in memory can be operated on and the 
result stored in one of the memory locations, 
all under the control of a single instruction. 
The TMS9980 processor used on this board is 
a limited version of its big brother and is 
mounted in a smaller 28 pin package that can 
address only 16384 bytes of memory (com- 
pared to 65536 bytes for the TMS99O0). Inci- 
dentally, when dealing with a 16-bit computer 
you must be careful to distinguish between 
words and bytes since bytes arc 8 bits long but 
words 16 bits. 

The on-board terminal includes keys for the 
full alphabet and punctuation marks, although 
several are difficult to identify because of the 
limitations of a 7-segment LED display. Al- 
though the board can be interfaced to an RS- 
232- or TTY-type terminal, the only advantage 
this approach offers is a permanent hard- copy 
record. The built-in terminal gives full system 
control in contrast to the partial control imple- 
mented by many single-board systems. 

Output can be directed to the terminal's ten- 
digit LED display, an external terminal, the 
piezoelectric speaker, or the four single-ele- 
ment LED's. The companion text has a Morse 
code program that produces speaker output 
tones in response to pressing the alphabetic 
keys. Amazingly short, this program is an 
excellent example of the power of the 16-bit 
processor. 

Programs can be stored on audio cassette 
tape using the on-board interface circuitry. 
Level detectors and amplifier stages are in- 
cluded to produce reliable recording on stan- 
dard cassette recorders that have auxiliary 
input and earphone output jacks. 

The Unibug monitor responds to 15 com- 
mands that let the user save and load pro- 
grams, call the assembler, and read and modify 
memory, pointers, registers and the program 
counter. Programs can be executed up to a 
specified breakpoint. 

The ROM-based assembler converts assem- 
bly language mnemonics to machine code. 
Two-character symbols can be defined and 
backward references are satisfied as sufficient 
information is gathered. The assembler can be 
reentered at will without destroying the sym- 
bol table. 

The standard IK RAM user memory is 
expandable (o 2K on-board, and up to 8K 
external memory can be added. Sockets are 
included for a TMS9902 and other parts to 
implement an EIA RS-232C or TTY serial 
interface port. The board includes space for a 
cassette recorder motor relay that is controlled 
continued on page 38 



Beckman brings a 
ew dimension to hand held 
Digital Multimeters 




True RMS capability 
at an affordable price 

Now you can measure the exact power content 
of any signal — regardless of waveform. Beckman 
delivers the new TECH™ 330 multimeter with 
true RMS capability and many more fine 
performance features for just $200. 

Unlike the common average responding 
multimeters calibrated to measure only sine waves, 
the TECH 330 with true RMS capability gives 
you accurate readings of both sine and 
non-sine waveforms. 

True RMS makes a significant difference in 
accuracy when measuring switching power 
supplies, flyback power circuits, SCR or TRIAC 
controlled power supplies or any other circuit 
generating a non-sine signal. 

The TECH 330 also accurately measures the 
entire audio band up to 20 kHz. But that's 
not all you can expect from Beckman's 
top-of-the-line multimeter. 



VYv Wyvw 



Measurement Comparison Chart 


WaiMfnmM 
(Peik = 1 Volt) 


Average 

Responding 
Meier 


Backmin 
TECH 330 


Correct 
Reeding 


S I n* Wivs 


0.707V 


0.707V 


0,707V 


Full WJTO HKtiljed Sine WflV* 

rYYYYVVYVV^ 


0.I9SV 


0.707V 


0,707V 


Half Wiva Rtcllftfrd Sin* W«va 


0.382V 


0.500V 


0-5WV 


Squani Wavft 

o juuinnjuuinr 


1.110V 


1.000V 


1.000V 


Triangula* Sawiocth W-.™ 

»V/WVWW 


O.SiSV 


0.577V 


0.577V 



You also get 0. 1 % basic dcV accuracy, instant 
continuity checks, 10 amp current Tanges, a 
separate diode test function, 22 megohm dcV input 
impedance, and an easy-to-use rotary switch. 

With so much capability in hand, you'll be able 
to depend on the TECH 330 for a long time. 
That's why Beckman designed it tough enough 
to go the distance. 

Enclosed in a rugged water-resistant case, the 
TECH 330 can take a 6-foot fall onto concrete and 
still perform up to spec. And to further ensure 
reliable, trouble-free operation, the TECH 330 
gives you 1500 Vdc overload protection, RF 
shielding, 2000-hour battery life, gold switch 
contacts, and fewer electronic components 
to worry about. 

Add another dimension to your world of 
electronics. Visit your Beckman distributor today 
for more information on the TECH 330 and 
Beckman's complete line of digital multimeters, 
starting at $110. 

To find out which of our 500 distributors is 
nearest you, call: (7 1 4) 993-8 803 or write Beckman 
Instruments, Inc., Electro-Products Group, 
2500 Harbor Boulevard, Fullerton, CA 92634. 

BECKMAN 

CIRCLE 12 ON FREE INFORMATION CARD 



"If you're going to learn 
electronics, you might 
as well learn it right!" 



to 
o 

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111 

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a 

34 




'!DowY settle for less. 
Especially when it comes 
to career training, . . because 
everything else in your life 
may depend on it That's 
why you ought to pick CIEF 



TouVe probably wen ad- 
vertisements from other 
electronics schools. Maybe you 
think they're all the same. 
They're liotJ 

CDE Is the largest indepen- 
dent home study school in the 
world that specializes exclu- 
sively in electronics. 



Meet the Electronics 
Specialists. 

When you pick an electronics 
school, you're getting ready to invest 
some time and money. And your 
whole future depends on the educa- 
tion you get in return. 

That's why it makes so much 
sense to go with number one , . . with 
the specialists. , .with CIEI 

There's no such thing as 
bargain education. 

If you talked with some of our 
graduates, chances are you'd find a 
lot of them shopped around for their 
training. Not for the lowest priced 
but for the best. They pretty much 
knew what was available when they 
picked CEE as number one. 

We don't promise you the moon. 
We do promise you a proven way to 
build valuable career skills. The CEE 
faculty and staff are dedicated to 
that. When you graduate, your di- 
ploma shows employers you know 
what you're about. Today, it's pretty 
hard to put a price on that. 

Because we're special- 
ists, we have to stay 
ahead. 

At CIE, we've got a position of 
leadership to maintain. Here are 
some of the ways w T e hang onto it . . . 

Our step- by-step learning 
includes "haud§-ou" 
training. 

At CIE, we believe theory is 
important. And our famous 
Auto-Programmed* Lessons teach 
you the principles in logical steps. 

But professionals need more 
dian theory. Thatte why some of our 
courses train you to use tools of the 
trade like a 5 MHz triggered- sweep, 
solid-state oscilloscope you build 
yourself— and use to practice trouble- 
shooting. Or a Digital Learning 
Laboratory to apply the digital theory 
essential to keep pace with electronics 
in the eighties. 

Our specialists offer you 
personal attention. 

Sometimes, you may even have 
a question about a specific lesson. 
Fine. Write it down and mail it in. 
Our experts will answer you 
promptly in writing. You may even 
get the specialized knowledge of all 
the CEE specialists. And the answer 
you get becomes a part of your per- 
manent reference file. You may find 
this even better than having a class- 
room teacher. 



Pick the pace that's right 
for you. 

CEE understands people need 
to learn at their own pace. There's no 
pressure to keep up ... no slow 
learners hold you back. If you're a 
beginner, you start with the basics. 
If you already know some elec- 
tronics, you move ahead to your 
own level. 

Enjoy the promptness of 

CIE's "same day*' grading 
cycle. 

When we receive your lesson 
before noon Monday through Satur- 
day, we grade it and mail it back— 
the same day. You find out quickly 
how well you're doing! 

CIE can prepare you for 
your FCC License. 

For some electronics Jobs, you 
must have your FCC License. For 
others, employers often consider it a 
mark in your favor. Either wav, it's 
government-certified proof of your , 
specific knowledge and skills I 

More than half of CIE's courses 
prepare you to pass the government- 
administered exam. In continuing 
surveys, nearly 4 out of 5 CEE gradu- 
ates who take the exam get their 
Licenses! 



For professionals only. 

CLE training is not for the hobby- 
ist. It's for people who are willing to 
roll up their sleeves and go to work 
... to budd a career. The work can be 
hard, sure. But the benefits are 
worth It. 

Send for more details 
and a FREE school 
catalog. 

Mad the card today. If it's gone, 
cut out and mail the coupon. You'll 
get a FREE school catalog plus com- 
plete Information on independent 
home study. For your convenience, 
we'll try to have a CEE representa- 
tive contact you to answer any ques- 
tions you may have. 

Mad the card or the coupon or 
write CLE (mentioning name and 
date of this magazine) at: 1776 East 
17th Street, Cleveland, Ohio 441 14. 




Cleveland Institute of Electronics, Inc. 

177S East 17th Street. Cleveland. Ohio 44114 
Accredited Member National Home Study Council 



LJ If JiS ... I want the best of everything! Send me my FREE CIE school 
catalog — including details about troubleshooting courses— plus my FREE package 
of home study information. RE .»7 

Print Name . 



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Age 

Check boxfor G.I. Bill Information: □ Veteran 

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§ 
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m mii Instant. 

OR COMING UP SHORT 



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EQUIPMENT REPORTS 

continued from page 32 



by the ROM operating system when loading 
and saving programs. Replacing the processor 
with a higher performance unit, and changing 
the crystal and some other components, in- 
creases the clock frequency from 2 to 8 
MHz. 

The TM990/1S9 University Module is 
priced at S299 and the optional power supply is 
$65. The TM990/IS9 is one of the better eval- 
uation/learning modules available for those 
really serious about learning microprocessors 
from the ground up, starting at the machine 
and assembly language level. It can be ex- 
panded as a development board for those lim- 
ited in capital, but more sophisticated systems 
are available for those interested in developing 
real applications for the 9900 processor series. 
Texas Instruments Incorporated, P.O. Box 
1443, M/S 6404, Houston, Texas 77001. R-E 

VIZ Model WR515B Color- 
Bar Signalyst 




38 



CIRCLE 49 ON FREE INFORMATION CARD 



CIRCLE 105 ON FREE INFORMATION CARD 
THE MODEL WR5I5B COLOR-BAR GENERATOR 

from the VIZ Manufacturing Company (335 
E. Price St., Philadelphia, PA 19144) is called 
the Color Bar Signal ist and is really a versatile 
instrument. It will provide all of the test sig- 
nals you need for analyzing the signal circuits 
of any color TV receiver. This includes an RF 
output on Channel 3 or Channel 4, an IF out- 
put and a video output. In result, signal-injec- 
tion can be used in any section of the set. A 
switchable 4.5 MHz sound IF carrier is also 
used, unmodulated. 

The model WR5I5B can generate an amaz- 
ing variety of test patterns. You can get the 
10- bar gated- rain bow pattern in three differ- 
ent versions, each with its own special use. In 
the standard 10- bar pattern, the 6th bar (blue) 
is marked for instant identification. Next is the 
same 10-bar pattern, but with no burst. This 
lets you set up color sync circuits for zero with- 
out hooking up a lot of jumpers, or testing this 
without even taking the back off the set. Last is 
the bar pattern, with the Y, or luminance, sig- 
nal added. 

There are three solid-color rasters; red, 
green and blue. The red can be used for check- 
ing and adjusting purity on the older sets, and 
[he green for the later models with in-line 
tubes. Still another raster, called a Color Trio, 
has fully-saturated sections of each primary 
color; good quick-check for picture tube sus- 
pected of having one weak gun. 

For video circuit tests and similar adjust- 
ments, there is a black-and-white Gray Quad; 
the four quadrants of the screen are white, 
light gray, dark gray and black. 

For convergence, there's a hatehdot pattern 
which consists of a Crosshatch with dots 
around the outer edges and one in the center. 
For those who still have good eyesight, the old 
familiar dot pattern is here with the center dot 
continued on page 40 



Start learning and computing for only $129.95 wit h a Netronics 8085-based 
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From the first day you own Explorer/65, you begin 
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LEVEL "A" SPECIFICATIONS 
ExplareryBS's Level "A" system features the advanced 
Intel BOBS cpu, an 83S5 ROM with 2k deluxe monitor/ 
operating system, and an advanced 8155 RAM I/O . . . 
all on a single motherboard with room for RAM /ROM/ 
PROM/EPROM and S4QQ expansion, plus generous 
prototyping space. 

PC Board: Class epoxy. plated through holes with 
solder mask. ■ I/O: Provisions for 25-pin (DB25) con- 
nector for terminal serial I/O, which can also support a 
paper tape reader cassette tape recorder input and 
output . . . cassette (ape control output . , . LED output 
indicator on SOD (serial output) line , . . printer inter- 
face (less drivers) . . . total of four 8-bil plus one G-bit 
I/O ports. • Crystal Frequency; B.144 MHz. ■ Control 
Switches: Reset and user (RST 7.5) interrupt . . addi- 
tional provisions for RST 5.5. 6,5 and TRAP interrupts 
onboard. ■ Counter/Timer Programmable. 14-bit bi- 
nary. * System RAM: 256 bytes located at FBOQ, ideal 
for smaller systems and for use as an isolated slack 
area in expanded systems . . , RAM expandable to M K 
via S'lOG bus or 4k on motherboard. 

System Monitor (Terminal Version): 2k bytes of 
deluxe system monitor ROM located at FjHJfl, leaving 
ffi&B free Tor user RAM /ROM. Features include tape 
load with labeling . . . examine/change contents nf 
memory . . . insert data . , . warm start . . . examine and 
change all registers . . , single step with register display 
at each break point, a debugginft/t raining feature ... go 
to execution address . . . move blocks of memory from 
one location to another. . . fill blocks of memory with a 
constant , . display blocks of memory . . , automatic 
baud rate selection to 9600 baud , . . variable display 
line length control (1-255 characters/line) . . . chan- 
nelized I/O monitor routine with 6-bit parallel output 
for high-speed printer . . . serial console in and console 
out channel so that monitor can communicate with I/O 
ports. 

Systc m Man i t or (1 lex Keypad /Di splay Version ) : 
Tape load with labeling . . tape dump with labeling 
. . . examinn/change contents of memory . . . insert dnln 
. . warm start . . examine and change all agisters . . 




single step with register display at each break point . . . 
gcj In execution address. Level "A" in this version 
makes a perfect controller for industrial applications, 
and is programmed using Ihe Nefronics Hex Keypad/ 
Display It is low cost. pnrfiHil for thinners 
HEX KEYPAD/DISPLAY SPECIFICATIONS 
Calculator type keypad with 24 system defined and 16 
useT'defined kevs. Six digit calculator- type display, 
• that displays full address plus data as well as register 
and status information. 
LEVEL "8" SPECIHCATIONS 
Level "B" provides the S-100 signals plus buffers/ 
drivers to support up to six S-100 mis boards, and In- 
cludes: address decoding for onboard 4k RAM expan- 
sion selec|ahle in 4k blocks . address decoding for 
onboard ftk EPROM expansion selectable in 8k blocks 
. address and data bus drivers foronboard expansion 
. . . wail slalegeneralortjumpttrselitftableK to allow the 
Use or slower memories . . . two separates volt regula- 
tors. 

LEVEL "C" SPECIHCATIONS 
Level "C" expands Explore r/B5's motherboard with a 
card cage, allowing you to plus up to six S-100 cards 
directly into the motherboard. Both cage and caid are 
neatly contained inside Explorer's deluxe steel 
cabinet. Level C" includes a sheet metal superstruc- 
ture, a 5- card, gold plated S-100 nxlension PC board 
that plugs into the motherboard, fust add required 
number of fi-100 connectors. 




mil 25G bytes located in the 8155A) The static RAM 
can be located anywhere from HffQ9 tu EFFF in -Ik 
blocks 

LEVEL "E" SPECIFICATIONS 
Level "E" adds sockets for 8k of EPROM to use the 
popular Intel 2716 ortheTI 2516. It includes all sockets, 
power supply regulator, heal sink, filtering and decou- 
pling components Sockets may also be used for 2k x B 
RAM IC's (allowing for up to 12k of onboard RAM) 
DISK DRIVE SPECIFICATIONS 

• A" CONTROL DATA CORP. * Dita capacity 401 016 bytes 
prafeHEaadtdrivt jS-D). 802,032 btfes (DD). 

• L5] i nntr -iI-it unformatted. 

• Wnle protect. * Acosj time. 25rr» {one 

• Singlffur double deniily. track}. 
DISK CONTROLLER/ I/O BOARD 
SPECIFICATIONS 



• Conl.-ttta up io four B" d nvca 

• 1771 A LSI (SD r floppy d»k 
controller. 

• Onboard data acpanilur 
t IBM compatible). 

• ZSerid I/O parti 

• AutohooHodisksii'l^jn 
when lyalem rwuL 



• 2710 PROM socket included 
for use In custom 

applications. 

* : 'iii:-.u[i| ; r. .1 il conln ;lh .1 

• Onboard I/O baud rale 

Lynsir.in.f. aiI.K'WItmik! 

* Double-sided PC board 

:"!,:■..<■;■■■:.;.' 



LEVEL "D" SPECIFICATIONS 
Level "D" provides 4k of RAM. power supply regula- 
tion, filtering decoupling compunents and sockets to 
expand your Explorer/85 memory Io 4k (plus Ihe origi- 



BISK DRIVE CABINET/POWER SUPPLY 
• Deluxe sleel unbind with individual power supply for max- 
imum rMliahiljiy nnd liability. 

ORDER A COORDINATED 
EXPLORER/85 APPLICATIONS 
PAK! 

Beginner's Pik (Save JM.O0!) — Buy Level "A" (Ter- 
minal Version] with Monitor Source Listing and AP-1 
5-amp Power Supply: (regular price S199.95). now al 
SPECIAL PRICE: $169.96 plus post. & insur 
Experimenter's Pale II (Save 153.40!) — Buy Level 
"A" (Hex Key pad /Display Version) with Hex 
Keypad/Display. Intel B0&5 User Manual. Level "A" 
Hex Monitor Source Listing, and AP-1 5-amp Power 
Supply, (regular price S279.35). all at SPECIAL 
PRICE: $219.35 plus post. & insur 
Special Microsoft BASIC Pak (Save S 103.00!) — In- 
cludes L^vel "A" (Terminal Version). Level "B". 
Level "D" (4k RAM). Level "E". Bk Micrasofl in 
ROM. Intel 8085 User Manual, Level "A" Monitor 
Source Listing, and AP-1 5-amp Power Supply: (rcgu- 
lar price M39.70). now yours at SPECIAL PRICE: 
1329.95 plus post. & insur. 

ADD A TERMINAL WITH CABINET, 
GET A FREE RF MODULATOR: Save 
over $114 al [his SPECIAL PRICE: $499.95 
plus post. & insur. 
Special B ' D is k Edi I ion E xpl orcr/BS (Save over $1B4! ( 
— Includes disk-version Level "A", l^tvel "B". two 
S-100 connectors and brackets, disk controller. 64k 
RAM, AP-1 5-amp powersupply. Explorer/B5 deluxe 
sleel cabinet, cabinet fan. B" SD/DD disk drive from 
famous CONTROL DATA CORP (not a hobby 
brand!), drive cabinet with power supply, and drive 
cable set-up for two drives. This package includes 
everything but terminal and printers (see coupon lor 
them]. Regular price $1630.30. all yours in kit al 
SPECIAL PRICE: $1499.95 plus post. & insur. Wired 
and tested, only $1799.95. 

Special E Complete Business Software Pak (Save 
5625.00!) — Includes CP/M 2.0, Microsoft BASIC. 
CieneraE Lt-dger. Accounts Receivable. Aixounts 
Payable. Payroll Package; [regular price S132S]. yours 
now at SPECIAL PRICE: $699,95. 



Please send the items checked below: 
D Ksplorer. 85 Level 'IV Ut| Terminal Venii.nl « I2J.95 plu* 

S3 post & insur. 
HI ExplOfCT/SS Level "A" Ul ( Hex Keypad ^Display Virrs.nnl 

$129,9$ plus S3 rx»t. & insur 
U 8k AfcrosoTt BASIC on cassette tape. St4 JS Dostpaid. 

□ SkMlcrtKOft B.4SIC In ROM Ml [requires Lcvih B" D" anil 
"E") . nS.U plus S2 post a insur 

D Level "B"(S-t0O)kll S4M$plusS2rjr»l * insur 

n Level "l? ■ (S- 100 6-card eipander) Ml UMS pi . n s: p m 

& insur. 
D Level "D" |4k RAMI kit IW.9S plus S2 poat f. insur 

□ Level "f (SFKOM.'IWIritl Ml SS.9S plus 50c p*h 

□ Deluxe Steel cabtnet fur Explnn>rjB5 $4IUU plus S3 pisi 
A insur 

□ Fan For Ot„ net SI 5.00 plus St nu |>,^l He insur. 

D *Sai keyboard Computer Terminal Idt: f,-.iluri.« n full I2S 
charactof --ih uftl case: full cunof []>ntml. 75 ohm viden 
output, convertible la beudot uulput. se!,H.-1ubl,! baud rule 
RS232(1ur 20 ma IA). 32 or EH character: by 111 line formals, 
and cm be usi-d with eilhera CRT mimttarnf a TV set lif ynu 
have an RF mmlulaliiO $149,95 plus W t» |»mI a uuiir 
ZA OeUnc Sted CeWnet for ASCII kuylnnnlflennioal . 
$19.95 plus 52 50 post ft insur 

D NewlTemDnaliMoollor:!^.,' photo) Sam. 1 features .is above. 
except 12" monitor with keyboard and lernllnftl is in deluxe 
abujle cabinet: kil $399,95 plus $7 pott. * fttsur 

D Hazelline lennlnals: [ >nr prices ichi lew to que in- — CALL US 

D Lear-Stgler lentil tutls.' printers: tinr pn, i's i.*. Vw tu cpniie 
CUIUS 

P Ilex Keypad/ Us play kit $69.95 phis 52 post A insur 



D AP-1 POHtr Supply kit ±BV ft 5 amps I in deluxe sl,s-l cabinet 
539.95 plus $2 post. & Mviur 

Z Cold haled s- EM bus Conner tors $4A5..,n.!i pistpuud 
D RF Modofatorldt Ealtowfl you Io mttyoiirTV sei as a m. miuin 

. . .SB 95 pOSlp«"l. 

□ I li RAM Id t ; > 1 1 :. ! I .. i. .r, 1 . ■ - 1 >. i re [-, ■. i M I. . $1 MB5 plus $2 
pis, ft insur 

D 32k HAM kit S299.95 plus S2 post ft msur 
: 4Bk RAM kit S 39(1 95 plus & pisl ft insur 
-64HWMUI WM.95plusS2pisl » insur 
G 18k HAM Einanslrm tdl [to expand any at Ihe nlx.ve in ltd 

blocks up to (Hk) S99.95 plus Mptisl S insur nadl 
.. Intel 8085 qw Users' Manual (7.50 pislpml 
_ 1 1 Video Monllw 1 1.1 M H ? 1>. . ii. I u- 1 , 1 1 h i $ 1 39.05 pli is ST, 

pisl A insur. 

□ Beoinner's Pak [w nbnvel $I8BJU pEus 54 p. j, .i A .nsur 

! i ExpertrrBoter^ Pak n» ,il».ve) S2ID.9S plus 5ii pisi ft 

fmiir 
a Special HI erosotl BASJC Pak Mllhoot TMtrinal i u s ■ . . I . n ,■ i 

£329.05 plus $7 post ft insur 

a Seme as above, plus ASni Keyboard Terminal Wtlt Cabtnet, 
Gel Free KF Modulator (see annvp) $488.95 plus sin post 
ft insur 
a Special 8 " Disk Edl lion FJplareri85 i si , n I » ml S 1 4 99 95 
pins S-i, fwisl ft insur 
: W red ft Tt?i ted SI 799.95 pi us 52(5 n, k1 . ft insur 
D Btlra B" CDC Floppy Drives $499.95 plus $12 posL ft insur. 
D Caranet ft Power Supply For Drive $BB.95plus$l|Hisi ft 
insur 

□ Drive Cable set-up Far Two Drives S25 plus Si M i».-j ft 



l: Disk controller Board m th L. o ports s 1 99.95 pi 1 1 ■. S2 p, ■ s i 

ft insur. 
D Special: Complete Business sanware Pak (see above) 

$000.90 [X!S I [Ml! I 

SiOlJl SEPAaATELV 
" LP. 1 M 1 .4 $ 1 00 p. is I p ii. I 
: IPM!.« tt$0rH«lpuil. 
n Mtcroson BASIC S325p.slp.iu! 
Intel U0B5 cpu csct sun ml 57 90 postpaid. 

' level "A" Monitor Source Listing wptBtpaid 
^ conlintm.il i .SA [:r,illl raid Buyers Outside ComKllkut |^ 

m CALL TOLL FREE: 800-24 3-7428 I 

To Oriler Frum Connecticut Clr For Techmisil 
^ Assislanci?. mil (2031 W4-U375 ^ 

Tiit.il Knclosi'il (Ciinn res. itdd sttlra lux) S 

Paid B) 

n Personal Check D Cashier's Check/Money Order 



U VISA 
Accl. Nil. 
Signal li ret 
Prinl 
Namtt _ 
ArlrlrrrsH 

eily 

Slate 



D Master Charse (Bank No ) 

. Exp Dale 



.Zip. 



NETR0NICS Rttsearch & Devclopmenl Ltd, 
ill 333 LilCllfidtl ROntl, New Miltord, CT 06776 



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IS 

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CIRCLE 11 ON FREE INFORMATION CARD 



39 



8 

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DC 

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6 

40 




a Shure stylus 
is a sound 
investment 

A new stylus (needle) can actually 
save you money. Even a precision 
crafted diamond stylus eventually 
wears out, and a worn or broken 
stylus tip can damage your 
records in a single play! Protect 
your records by checking your 
stylus at least once a year. Your 
Shure dealer can inspect it, and 
if necessary, replace your 
stylus with a Genuine Shure 
replacement stylus that will 
bring your cartridge right back 
to its original specifications. 



iSvjto* 









ft eN^ 



stop 



O riof^ a0 ° e 



Shure Brothers Inc., 222 HartreyAve. 
Evanston, IL 60204 
In Canada: 

A. C. Simmonds & Sons Limited. 
Man u fadurers of hig h f id elity 
components, microphones, 
sound systems and related circuitry. 



EQUIPMENT REPORTS 

continued from page 38 



CIRCLE 76 OK FREE INFORMATION CARD 



blanked for centering purposes. The last pat- 
tern is called the Superpulsc. This is a black 
screen, with a large white rectangle centered in 
it. This checks video-circuit high and low fre- 
quency response, contrast and other things. On 
the scope, this shows a very sharp square wave 
pulse, useful for signal -tracing and locating 
troubles in these stages. 

In normal operation, all patterns are non- 
interlaced; this gives a more stable picture, 
especially when the convergence patterns arc 
in use. In some of the later receivers, interlaced 
scanning must be used. All of the WRSI5B 
patterns can be interlaced; just turn the pat- 
tern-selector switch to start PLACE and let go; 
it's spring-return. When the power is turned 
off, the instrument goes back to non-interlace 
scanning. 

The RF, IF and video levels are all variable, 
RF from 5 microvolts up to 100 mV into a 
75-ohm input, and 10 microvolts up to 200 mV 
into 300 ohms. The IF signal level can be had 
up to 100 mV. The video output goes from to 
1 .7 volts peak-to-peak, and this can be set for 
either positive- or negative-going sync. 

The RF/IF and video outputs may be used 
at the same time. One good use for the simulta- 
neous output feature is to feed the video signal 
into the upper trace of a dual-trace scope and 
then feed the RF into the set antenna termi- 
nals. Monitoring the video detector output will 
show any problems in tuner/IF/AGC, etc. 
The demodulated signal should be exactly the 
same as the video on the top trace. Any of the 
patterns may be used for this purpose. For sta- 
ble patterns, both horizontal- and vertical-sync 
trigger pulses are provided from jacks on the 
front panel. Some patterns are hard to lock on 
a conventional scope. The bar pattern, for 
example, makes a comb trace with 10 peaks of 
the same amplitude. Using the sync and the 
trigger signal from the WR5ISB, the wave- 
form will be rock steady. 

The instruction manual is detailed, well 
illustrated with raster patterns and scope wave- 
forms. Sections of the manual give detailed 
instructions, waveforms, etc., for making many 
tests in color TV sets. This is a very compact 
and useful TV test instrument and one that 
will make many more tests that can come in 
very handy! The model WR515B has a sug- 
gested retail price of $275. Ft-E 



IGM Model BAX-1 
Broadband Amplifier 

FOR YEARS. ICM (FORMERLY KNOWN AS THE 

International Crystal Manufacturing Compa- 
ny) provided simple kits for amateurs and 
experimenters. Most of those were crystal 
oscillator kits. 

More recently, ICM has been producing 
accessory RF circuitry such as mixers and 
amplifiers. The model BAX-i broadband RF 
amplifier is one, so we decided to look at it. 

Basically, the model BAX-I is an untuned 
direct -coupled wideband amplifier, designed to 
increase all signal levels from audio to VHF. 
Its rated specifications are as follows: 20 
Hz-150 MHz. Maximum gain occurs near l 
MHz (30 dB) and the gain drops off gradually 
into the VHF region so that at 150 MHz it is 6 
dB. Working impedance is from 50 to 500 
ohms. Maximum input level, 0.01 volt AC. At 
continued on page 42 



NOW AVAILABLE! 



WATT WIZARD 

POWER FACTOR CONTROLLER CUTS 
THE COST OF RUNNING ELECTRIC 
APPLIANCES BY AS MUCH AS 
50% - AND YOU CAN EVEN SEE THE 
SAVINGS! 



TM 



For over a year now, in magazines 
and newspapers the world over, there 
have been enthusiastic write-ups on a 
remarkable new device that can cut 
your electric bill while helping the U.S. 
save huge quantities of tuel. 

"The NASA/Nola power saver," 
wrote a Popular Science senior editor, 
"was developed by Frank Nota at 
NASA's Flight Center in a program 
to reduce power consumption in space- 
craft motors. No la calls it a PFC — 
power-factor controller. I prefer to call 
ft a power saver, however, because 
that's what it does." 



NASA TESTED IT 

According to NASA documents, "The 
device has been tested at Marshall 
Center on over 40 types of motors, 
with power savings ranging up to 60%, 
depending on the loading. The motors 
tested were both single-phase and 
three-phase, ranging from Vi H.P. to 5 
H.P. Most motors will show up to 40 — 
50% savings when running lightly load- 
ed or unloaded, and some will show 
5-to-7% savings at rated load." 

NASA's Technical Support Package 
showed that "The Power Factor Con- 
troller applies to induction type electric 
motors — the most commonly used 
type in all major home appliances and 
the most commonly used by industry." 



HOW IT SAVES POWER 
Popular Electronics explained it this 
way: "AC Induction motors character- 
istically run at a nearly constant speed 
that's fixed by power-line frequency 
and independent of load and supply 
voltage. When heavily loaded, the 
motor draws line current that is 
nearly in phase with the applied volt- 
age. ..Under light load conditions, the 
motor develops less torque by allowing 
more lag between the voltage and the 
current. This reduces the power factor 
while leaving the current essentially 
the same In magnitude. 

"To minimize this waste, Nola's 
device monitors the motor's power fac- 
tor and when it detects light load condi- 
tions, it reduces the supply voltage 

The current, now more nearly in phase 
with the voltage, therefore does as 
much useful work as before, but it and 
the voltage are smaller, resulting in a 
net savings of electric power." 



THE SAVINGS CAN ADD UP 

The cost of electric power keeps 
going up. In 1980-81 and beyond you'll 
pay more and more for the privilege of 
running your electric appliances. 

Right now, the typical consumer pays 
about $8 per month to operate a 16.5 
cu. ft. frost-free freezer... $10 to run a 
17.5 cu ft. frost-free refrigerator... and 



National Aeronautics 

and Space Administration 

Patent No. 4,052,648 



about $60 for an air conditioner used 
during summer months. That's what 
you're paying to run just one of these 
appliances per year. 

Nola's power saver can soon pay for 
itself, then start reducing your electric 
bills. Until now, the device has not 
been available — except for industrial 
models priced at $80 or more. 



INTRODUCING THE WATT WIZARD 

Cynex, an American manufacturer of 
electrical and electronic products and a 
prime contractor for the U.S. Army, 
has been licensed by NASA to manu- 
facture Frank Nola's power saver. Cy- 
nex calls it the Watt Wizard. 

The "Watt Wizard" says Ray 
Beauchea, the firm's Marketing 
Director, regulates the voltage fed 
into an induction motor making the 
motors run more efficiently and quieter, 
while lengthening motor life. 





The Watt Wizard features a unique, constant 
power saving readout. So you can constantly 
monitor you're energy savings. 

SIMPLE TO USE 

Cynex makes several models of the 
Watt Wizard (ail with solid state de- 
sign), including the 110 v. AC plug-in 
model we're offering. It's for single 
phase fractional H.P. motors (less than 
1 H.P.) used in most freezers, refriger- 
ators, fans, swimming pool pumps, 
vacuum cleaners, sewing machines, etc. 

Simply plug the Watt Wizard into 
any electrical outlet, then plug the ap- 
pliance into the Watt Wizard. There's 
no wiring required. Unlike some com- 
petitor's models (if and when available), 
the appliance does not have to be 
turned on before being plugged into 
the power saver. You can leave the 
appliance — whether on or off — plug- 
ged into the Watt Wizard all the time. 
Or you can move the Watt Wizard to 
various locations. 



OTHER MODELS AVAILABLE 

Air conditioners, washers and dryers 
require wire-in model. If you lack 
mechanical skill, you probably need an 
electrician to install it. We also offer it 
In 220 VAC single or three-phase. 

CIRCLE 40 ON FREE INFORMATION CARD 



EXCLUSIVE ADVANCE FEATURES 

The Watt Wizard also includes two 
more unique features which no compet- 
itor has. It's fused so if you accidentty 
overload the device, it won't burn out. 
Just change the fuse, which is available 
at any auto supply store. 

And Watt Wizard features a unique 
LEO readout, so you can actually tell, 
at any moment, exactly how much 
power you're saving — 10%, 20%, 
30%, 40% or 50%. This feature is 
available only on the Watt Wizard. 

There's a "power-on" light, too. And 
the Watt Wizard comes with the manu- 
facturers 1 year limited warranty. 



LOW COST - AND A TAX CREDIT 

We're offering the Watt Wizard for 
only $39.95, with immediate delivery. 
Want two? Then its just $37.95 each. 
Or splurge and get three at $34.95 
each. Wire-in models for heavy duty 
motors are $6 more for each unit. Add 
just $2.50 postage/ handling for each 
order (not each unit). 

And next year, when you fill out your 
tax return, you can deduct a full 15% 
energy tax credit-for additional savings. 

30-DAY MONEY-BACK GUARANTEE 

Try the Watt Wizard for up to 30 
days. If not completely satisfied, return 
it (insured) for a full refund. 

The sooner you send for the Watt 
Wizard, the more you can save on your 
electric bills. To order, send your check 
or money order to the address below. 
OrchargeittoyourVisa, MasterCharge, 
American Express, or Carte Blanche 
credit card. If using your charge card, 
you can also order via our toll-free 
phone number: 

800-257-7850 



(In New Jersey, 
N.J. residents 



Call: 800-322-8650) 
add 5% sales tax. 



Or mail your order to: 

^^■% INTERNATIONAL SALES GROUP 

%■■# THE IMAGINATION PEOPLE® 



Dept. RE10, Lakewood Plaza 
Lakewood, New Jersey 0S701 



O 

s 

O 
CO 
m 

3J 

(O 
CO 

o 



41 



EQUIPMENT REPORTS 

continued from page 40 



1 MHz, the maximum outpul level is 0,1 volt 
across 50 ohms (or 0.5 volls across 500 
ohms). 

The noise level is less than 10 microvolts at 
RF levels and it is under 0,5 millivolts at audio 
levels, Alt that is accomplished with a DC 
operating power or 9 to 15 volts at only 10 
milliamps. 

The specifications looked good, so wc assem- 
bled the kit. That was a snap since the kit 
contains only Iwo transistors, three capacitors 
and five resistors. Total assembly time, about 
1 5 minutes. The tiny '/;-inch square PC board 
is well marked with silk-screened parts identi- 
fications. Assembly instructions are adequate 
and clearly slated. Accompanying diagrams 




CIRCLE 106 ON FREE INFORMATION CARD 

assist in both accurate assembly and practical 
applications. 

Although there was a slight discrepancy 
between the eallout value for the two electro- 
lytic capacitors and their actual value, substitu- 



te 
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(C 
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uj 
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42 




Save money!. 



Sheer magic from 
the Wizard of VIZ 



VIZ SUPPLYSTSDO TWO JOBS 
FOR THE PRICE OF ONE 

Why buy a power supply and a voltmeter when a SUPPLYST will do both jobs. Every 
SUPPLYST is both a laboratory quality, fully regulated source of DC power and a dual 
digital voltmeter. That's real versatility! 

As a power supply, a SUPPLYST can be set to your desired "voltage" and your "current 

limit" by convenient panel controls. Instant pushbutton reset. You can continuously 
monitor either voltage or current on a clear LED digital readout. 

As a voltmeter, a SUPPLYST can be used to measure one or two external circuit voltages 
simultaneously— even while the unit is being used as a power supply! 

SUPPLYSTS come with output cable and one year parts and labor warranty. Available 
in four models— to meet a wide range of needs. 

See your local VIZ distributor. 




S*tt]le.0-50VOC.0-2A.TV(OvcJtmBteES0-99 9VDC.WP-r05S2'fO Single. 0-25VOC,0.4A.Twora)tmetefsO-99eVDC WP-706S240 




Dual. Two 0-2SYDC. 0-2A supplies I0-S0V0C In serlrel lira Trlpl«.Two0-Z0VDC.u-2AS)j|»liesl0-40VBCinseriBSl.OrtBWDC 
volimelws 0-99.9VDC. WP-T07 S299 (0-4AJ lised supol* Two lolttnews 0-999VDC WP-708 S333 



VIIZ 



VIZ Mfg. Co., 335 E. Price St., Philadelphia, PA 19144 
Over 70 teat instruments in the line 

CIRCLE 2 ON FREE INFORMATION CARD 



tion is obvious and should cause no confusion. 
Make certain to keep the leads short to insure 
the upper- frequency response of the amplifi- 
er. 

A package of hardware is included for 
mounting the completed board. 

The completed mode! BAX-1 amplifier 
board was connected to a 9- volt battery, and 
current was measured as the specified 10 mA. 
Shortwave amplification was checked by con- 
necting the board to a CB receiver. Signals 
were brought up from barely readable to 
extremely strong; we were impressed. 

Next, we tested VHF applications. The 
model BAX-1 also helped improve FM broad- 
cast signals. A mobile radiotelephone signal 
monitored near 152 MHz was raised from 
noisy audibility to nearly full quieting. The sig- 
nal strength of NOAA weather broadcasts at 
162.55 MHz was also increased, but not as 
much. It was clear that the amplifier gain was 
deteriorating rapidly in the mid-VHF board. 
Out of curiosity, wc attempted lo monitor a 
signal at 500 MHz with and without the Mod- 
el BAX-1 in line. At the 500- MHz frequency 
the amplifier became an attenuator — signals 
were way down! That was to be expected, and 
it became clear that the unit responded faith- 
fully to its specified parameters. 

It must be kept in mind that this is not a 
low-noise amplifier. A wideband amplifier will 
substantially boost the noise floor of the sys- 
tem right along with the signals. It is therefore 
recommended that the frequency limits of any 
amplifier, including the model BAX-1. be nar- 
rowed with some type of tuning. Only when 
extreme frequency agility will be necessary 
should the upper and lower limits be left wide 
open. We also recommend that the model 
BAX-1 be enclosed in some sort of shielding to 
reduce the amplification of any stray signal 
pickup. 

It became evident after only a few simply 
tests thai the imagination of an inveterate tin- 
kcrcr could run wild with this device. Here are 
some possible applications; 

1. VLF antenna preamplifier, connected 
at the antenna to overcome the capacitive 
losses associated with coaxial feed of a 
short antenna at low frequencies. 

2. A signal generator booster. The high 
gain could provide a considerable Increase 
in output for marginal applications. 

3. A shortwave preamplifier. Such a unit 
could provide the equivalent of up to five- 
S-units improvement on received signals. 
But you must remember that if it is un- 
tuned, the result could be a signal overload 
of the receiver's front and. 

4. A loop antenna preamplifier. Used in 
conjunction with a broadband direction- 
finding loop, the model BAX-1 can provide 
stronger signals to the receiver for moni- 
toring purposes. 

5. An instrumentation amplifier. Some 
signals are too small to provide meaningful 
inputs to oscilloscopes and other test in- 
struments; the model BAX-1 amplifier 
should help. 

6. An active bandpass filter. A variety of 
bandpass shaping techniques at audio and 
RF signal levels would be possible with 
feedback loops and tuned circuits connect- 
ed to the model BAX- 1. 

Best of all, the cost of the model BAX-l 
amplifier is extraordinarily low ($6.67). It 
would be hard to duplicate separate parts and 
PC board for the same price. It is manufac- 
tured by ICM, P. O. Box 32497, Oklahoma 
City, OK 73132. R-E 



The first personal computer 
farunder$20(X ~~ 



The Sinclair ZX80. 
A complete computer- 
only $199.95 plus $5.00 shipping. 

Now, for just $199.95, you can get a 
complete, powerful, full-function computer, 
matching or surpassing other personal 
computers costing several times more. 

It's the Sinclair ZX80, the computer that 
independent tests prove is faster than all 
previous personal computers. The compu 
ter that "Personal Computer World" gave 
5 stars for 'excellent value.' 

The ZX80 cuts away computer jargon 
and mystique. It takes you straight into 
BASIC, the most common, easy-to-use 
computer language. 

You simply take it out of the box, con- 
nect it to your TV, and turn it on. And if 
you want, you can use an ordinary cassette 
recorder to store programs. With the man- 
ual in your hand, you'll be running programs 
in an hour. Within a week, you'll be writing 
complex programs with confidence. 

All for under $200. 

Sophisticated design makes the 
ZX80 easy to learn, easy to use. 

We've packed the conventional computer 
onto fewer, more powerful LSI chips — 
including the Z80A microprocessor, the 
faster version of the famous Z80. This 
makes the ZX80 the world's first truly port- 
able computer (6V2" x 8V2" x Vh" and a mere 
12 oz.). The ZX80 also features a touch 
sensitive, wipe-clean keyboard and a 
32-character by 24-line display. 

Yet, with all this power, the ZX80 is easy 
to use, even for beginners. 





Your course in computing. 

The ZX80 comes complete with its own 
128-page guide to computing. The manual 
is perfect for hoth novice and expert. For 
every chapter of theory, there's a chapter 
of practice. So you learn by doing— not just 
by reading. It makes learning easy, exciting 
and enjoyable. 

The ZX80's advanced design 
features. 

Sinclair's 4K integer BASIC has perform- 
ance features you'd expect only on much 
larger and more expensive computers. 
These include: 

■ Unique 'one touch' entry. Key words 
(RUN, PRINT, LIST, etc.) have their own 
single-key entry and are stored as a single 
character to reduce typing and save 
memory space. 

■ Automatic error detection. A cursor 
identifies errors immediately to prevent 



entering 

programs with faults. 

■ Powerful text editing facilities. 

■ Also programmable in machine code. 

■ Excellent string handling capability— up 
to 26 string variables of any length. 

■ Graphics, with 22 standard symbols. 

■ Built-in random number generator for 
games and simulations. 

Sinclair's BASIC places no arbitrary re- 
strictions on you— with many other flexible 
features, such as variable names of any 
length. 

And the computer that can do so much 
for you now will do even more in the fu- 
ture. Options will include expansion of IK 
user memory to 16K, a plug-in 8K floating- 
point BASIC chip, applications software, 
and other peripherals. 
Order your ZX80 now! 

The ZX80 is available only by mail from 
Sinclair, a leading manufacturer of consumer 
electronics worldwide. We've already sold 
tens of thousands of units in Europe, so 
demand will be great. 

To order by mail, use the coupon below. 
But for fastest delivery, order by phone 
and charge to your Master Charge or VISA. 
The ZX80 is backed by a 30-day money- 
back guarantee, a 90-day limited warranty 
with a national service-by- mail facility, and 
extended service contracts are available for 
a minima] charge. 



Price includes TV and cassette connectors, 
AC adaptor, and 128-page manual. 

Ml you need to use your ZX80 is a standard TV 
(color or black and white). The ZXSO comes complete 
wiih connectors that easily hook up to the antenna 
terminals of your TV. Also Included is a connector for 
a portable cassette recorder, if you choose to store 
programs. (You use an ordinary blank cassetle.) 




The 2X80 is a family learning aid. Children 10 and 
above will quickly understand the principles of 
compu ting— and have fun learning. 

Phone orders: (203) 265-9171, Mon.-Fri. 

8 AM-6 PM EST. We'll deduct the cost of 
the call from your invoice. (For technical 
information, call (617) 367-2555, Mon.-Fri. 

9 AM-5 PM EST.) 



Sinclair Research Ltd., 475 Main St., 
P.O. Box 3027, Wallingford, CT 06492. 



To: Sinclair Research Ltd., 475 Main St., P.O. Box 3027, Waltingford, CT 06492. 

Please send me ZX80 personal compute r(s) at $199.95* each (US dollars), plus $5 

shipping. (Your ZX80 may be tax deductible.) 

I enclose a check/money order payable to Sinclair Research Ltd. for$ 

Name 




Address- 
City 



.State. 



.Zip. 



Occupation: 

Intended use of ZX80: . 



Age: 



Have you ever used a computer? D Yes □ No. 

Do you own another personal computer? □ Yes □ No. 



HE- 10-0 
*For Conn, deliveries, add 7% sales tax. 



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The computer 
that grows > 
as you grow. C 



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f\s your computer skills grow, so does your Heath H8 
System. New accessories and software are coming along 
all the time to make your system do more. 

Special bus design gives you seven plug-in board posi- 
tions so you can configure any combination of memory, 
I/O's and accessories. Vou can interchange boards. Add 
accessories. Build exactly the system you want. 

A wide selection of software makes your life more fun 
and more efficient. Hundreds of programs for business, 
home and family are available from Heath User's Group. 
Also two BASIC languages, Microsoft™ and Fortran" And 
more programs are being developed all the time. 

If you haven't seen the latest Heathkit catalog, you 
haven't seen the latest in computer fun. There's a new 
Music Synthesizer Board, new Speech Lab, new Color 



Visit your Healhkif Store 

In the U.S. and Canada visit your ' 
nearby Heathkit Electronic Cen- 
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the white pages of your phone book 
for the location nearest you. 
' Units of Veritechnology Electronics 
Corporation in the U.S. 
CIRCLE 52 ON FREE INFORMATION CARD 



CP-188 



Graphics Board and new Color Monitor. And coming 
soon, a new three-drive disk system. For an exciting 
, computer hobby, there's no more exciting computer 
than the Heath H8 — available fully assembled or in 
money-saving kit. 

For complete details and prices on the H8 and the com- 
plete line of Heath printers, terminals and accessories, 
write today for the new,/ree Heathkit Catalog, or pick 
one up at your nearby Heathkit Electronics Center. 



Heath* 

Send for 

FREE 
CATALOG 

Write to Heath Com- 
pany, Dept. 020-704 
Benton Harbor. MI 
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omplele support, 
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.Electronics 



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BUYERS GUIDE TO HOME COMPUTERS 

ifty peripherals and accessories Home computers -what's here and what's coming 



Dial up networks for home computers 



I 



Programming on your own level 



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This special section is written by Jules H. Gilder 



DON'T LET YOUR 
COMPUTER 
TALK DOWN * 
TO YOU. r 



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The more you know about 
microprocessors, the better you can 
communicate with your microcomputer. Sams 
has the latest books on understanding, 
programming and interfacing the most 
commonly-used microprocessors like the Z-80, 
6502, 6800, 6801 and 8085A. 

THESE BOOKS WILL HELP YOU GET MORE RESPECT 
FROM YOUR COMPUTER. 

6502 

D PROGRAMMING AND INTERFACING THE 6502, WITH EXPERIMENTS NO. 21651. 
By De Jong. $13.95 
□ 6502 SOFTWARE DESIGN. NO. 21656. By Scanlon. $10.50 

6800 & 6801 

D HOW TO PROGRAM & INTERFACE THE 6800. No. 21684. By Staugaard. $13.95. 

□ 6801, 68071 and 6803 MICROCOMPUTER PROGRAMMING AND INTERFACING. 
NO. 21726. By Staugaard. $12.95 

8085A 

D 8085A COOKBOOK. NO. 21697. By Titus & Titus. $12.95 
Z-80 

□ TRS-80 INTERFACING, BOOK 1. NO. 21633. By Titus. $8.95 

□ TRS-80 INTERFACING, BOOK 2. NO. 21739. By Titus. $9.95 

□ TRS-80 BOOKS 1 & 2. 2-VOLUME SET. NO. 21765. $17.50 

D Z-80 MICROCOMPUTER DESIGN PROJECTS. NO. 21682. By Barden. $12.95 

□ Z-80 MICROPROCESSOR PROGRAMMING & INTERFACING, BOOK 1. 
NO. 21609. By Nichols. Nichols & Rony. $10.95 

□ Z-80 MICROPROCESSOR PROGRAMMING & INTERFACING, BOOK 2. 
NO. 21610. By Nichols, Nichols & Rony. $12.95 

□ Z-80 MICROPROCESSOR PROGRAMMING & INTERFACING, BOOKS 1 & 2, 
2-VOLUME SET. NO. 21611. $21.95 



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4300 West 62nd Street, P.O, Box 7092 
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(317) 298-5400 
INDICATE QUANTITY IN BOXES ABOVE AND 
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Total amount of order $_ 



Add local sales tax where applicable $_ 
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□ CHECK □ MONEY ORDER 
D MASTER CHARGE □ VISA 



Expiration Date_ 

Interbank No 

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Radio Shack's TRS-80 is not perfect but a quarter-of-a-million owners find 

this computer to be the right piece of equipment at the right price. Some 

of the TRS-80's strengths and weaknesses are discussed here. 



SHORTLY AFTER THE PET COMPUTER APPEARED ON THE SCENE. 

in the early days of persona) microcomputing. The Radio 
Shack division of the Tandy Corporation announced their 
entry, the TRS-80 for $595. The price was right: it was com- 
petitive with the PET. then the only other lake-il-out-of- 
the-box, plug-it-into-the-wall computer. 

Radio Shack put on a strong promotional campaign and 
succeeded in selling its TRS-80 with Level I BASIC. But 
Radio Shack had a few things going for it. First, it had a 
tremendous distribution network which Commodore Busi- 
ness Machines, makers of the PET. couldn't come close to 
matching. Second, people knew who Radio Shack was, 
while Commodore was more of an unknown quantity. Third. 
Commodore was so impressed with its own achievements. 
that it demanded that anyone who wanted one of their com- 
puters pay in advance — and delivery time stretched to three 
or four months (and in many cases even more). Fourth, and 
worst. Commodore's attitude towards its customers was bad 
and support was bad. 

Well, with all of these things going for it, the TRS-80 
couldn't help but be a success. The tremendous demand 
really caught Radio Shack by surprise. Initial estimates 

vere for selling a few thousand computers. Sales to date. 

tree years later, are estimated to be over 250.000. Of 
course, along the way. Radio Shack learned that its Level I 

1 \S1C just wouldn't make it and it came out with Level II 

JASIC, from Microsoft; but the price of the machine also 
went up. Today, the 4K Level I machine is virtually a thing 



of the past and has been replaced in popularity by the I6K 
Level II unit. Also, Radio Shack has come out with a more 
business-oriented computer known as the Model II. Shown 
above are the three latest additions to the Radio Shack line of 
computers. At the top left is the TRS-80 Color Computer. It 
provides color graphics and features instant-load Program 
Pak soti ware. At the top right is the TRS-80 Model III. It's 
priced from S699 for the 4K version expandable to 32K plus 
disk storage for 52495. Also shown is the TRS-80 Pocket 
Computer. It weighs a mere ft ounces and is less than 7-inches 
long. You'll be hearing more about these units soon. 



System ts modular 

The basic TRS-80 Model I las the original TRS-80 is now 
called) computer is a modular unit that consists of four 
individual pieces: a 12-inch black-and-white video monitor, 
a 53-key keyboard/CPU unit that contains Microsoft BASI" 
in ROM and 4K to 16K of RAM. a power supply for the 
keyboard console, and a cassette tape recorder. 

With all those different units, you need three electrical 
outlets to set up your computer system. The problem be- 
comes still more acute if you add on an expansion interface 
and two disk drives: that will require another three outlets 
for a total of six. It quickly becomes apparent that one of the 
drawbacks of the TRS-80 design is its rat's nest of wiring. 
And all of these stray wires can only spell trouble for the 
high-speed digital circuits found in computers. Worst yet, 
none of the AC power cords are of the three-wire grounded 



1 

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47 




TABLE I— BASIC COMMANDS for Model I and Model II TRS-80's 



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Q 
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DC 



ABS 


ASC 


ATN 


CDBL 


CHR$ 


CINT 


CLEAR 


CLOCK 


CLOSE 


CLS 


COS 


CSNG 


CUD 


GUI 


cus 


DATA 


DATE$ 


DEFINT 


DEFN(X) 


DEFSNG 


DEFSTR 


DELETE 


DIM 


DIR 


EDIT 


END 


EOF 


ERL 


ERR 


ERROR 


FIELD 


FOR 


FRE 


FRES 


GET 


GOSUB 


IF-THEN-ELSE 


INKEY$ 


INPUT 


INSTR 


INT 


KILL 


LEN 


LET 


LEFT$ 


LIST 


LIST 


LLIST 


LOAD 


LOAD 


LOC 


LOF 


LOG 


LPOS 


LSET 


MERGE 


MIDS 


MKD$ 


MKI$ 


MKS$ 


NEW 


NEXT 


ON ERROR 


0N..GOSUB 


ON..GOTO 


OPEN 


POS 


PRINT 


PRINT® 


PUT 


READ 


REM 


RENAME 


RESET 


RESTORE 


RESUME 


RETURN 


RIGHTS 


RND 


RSET 


RUN 


SAVE 


SGN 


SIN 


STOP 


STR$ 


STRINGS 


SQR 


SYSTEM 


TAB 


TIMES 


TROFF 


TRON 


USR(N) 


VAL 










THE ORIGINAL TRS-80 with Level I BASIC and 4K of memory. 

type, although the video monitor power plug is polarized to 
prevent inserting it the wrong way. 

Once you successfully save a program on a cassette tape, 
you face several problems. The first is verifying it, or 
checking to see that it was properly recorded. To help you 
in that process, TRS-80 BASIC has a command called 
LOAD which will compare what has been recorded on a 
tape to what is actually in memory. Most of the time it works 
nicely, but recently I have found that it doesn't always 
work. I have loaded tapes into memory and then tried to 
verify the recently loaded program, with the one that is on 
the tape. The result was always BAD, even though a byte- 
by-byte check showed that both programs were the same. 

Once you do get your program recorded onto tape, you're 
going to want to load it back in one day. With most com- 
puters, if a tape is not being read in correctly, an error mes- 
sage is generated right away. That is not always the case 
with the TRS-80. More often than not, you'll sit and load a 
long program for three minutes, with everything appearing 
to go along smoothly. But then when you run the program 
an error message is generated. Listing the program at that 
point shows that you have loaded in three minutes worth 
of garbage, because your volume setting was not exactly 
set right. 

Having gotten those problems straightened out, a new 
one surfaced, this a lot more serious because it could occur 
randomly and wipe out my data. It occurs only in disk sys- 
tems and manifests itself by the disk suddenly rebooting 
itself, wiping out any program that was in memory at the 
time. I have been told that it is caused by power-line spikes 



and surges and that I should get a constant- voltage trans- 
former to clean that up. 

Adding a floppy-disk system to your TRS-80 provides you 
with an additional 50K of storage on your first disk and 86K 
of storage on diskettes in additional disk drives. Assuming 
that everything in your disk-based system is working fine, 
you can still encounter difficulty and ruin a good diskette 
in a snap. All you have to do is to try to turn the system 
power on or off while your diskette is in its drive, or try 
booting up your disk while a parallel printer is connected to 
your system, but not turned on. Any one of those actions 
could promptly wipe out your diskette. (Some other com- 
puters will also "crash" disks if the system is turned on or 
off while they are in the drive. It's a good idea to remove 
disks from their drives during these operations, unless your 
manual specifically states otherwise— Editor.) 

Expanding a basic l6K-system to more memory or disk- 
drive capability is expensive. In either case, you must pur- 
chase an expansion interface, which costs $300. Additional 
memory is sold by Radio Shack at $149 per I6K, which is 
33% to 50% more than you can get it for by yourself. The 
reason that the expansion interface is so expensive is that 
it comes with a disk controller capable of handling up to 
four disk drives. And you get it whether you want it or not. 
It also comes with a built-in parallel printer interface and a 
real-time clock which can be helpful in programs where it 
is necessary to keep track of time. 

Need help? 

While Radio Shack probably has a larger distribution 
network than any other personal computer manufacturer, 
you can't go into any one of them for technical help. If you 
need help, try and get to a Computer Center store. I have 
found that, in general, they have people who are quite knowl- 
edgeable and helpful. 

They keep making changes 

One annoying feature about Radio Shack, is that they 
keep making changes to the hardware without telling any- 
one, making independently-purchased hardware and soft- 
ware incompatible with the new versions. For example, 
early versions of the TRS-80 CPU brought out the 5-volt 
supply to the external connector. Later models eliminated 
that. Thus anyone designing an accessory that was to use 
that supply now had to provide his own power supply. A 
more recent change was in the ROM's supplied with the sys- 
tem. That can play havoc with the existing software on the 
market, because now some of the internal subroutines are 
not located where they were. In fact, some people have 
told me that the new ROM's have even resulted in problems 










A NUMBER of printers are available to run with the TRS-80. 
TABLE II 



ERASE — Cancels a dimensioned array and frees its mem- 
ory space. 

HEXS — Converts a decimal number to a hexadecimal 
string. 

NULL — Sends blanks at the end of a line (communica- 
tions). 

OCT$— Converts a decimal number to an octal string. 

RENUM— Renumbers program lines. 

RESET— Restores default system settings for all devices. 

SPACES — Prints a specified number of blank spaces. 

SPC— Prints spaces on video display. 

SWAP — Exchanges the values of two named variables. 

WIDTH— Sets line width for video display. 

ADDITIONAL OPERATORS: MOD, IMP, EQV. XOR (Inte- 
ger Division), 




with some Radio Shack-supplied software, which will no 
longer run in the new machines. And nowhere is the change 
documented, except for a short note in the new user's man- 
ual that states there will be two fewer bytes of free memory 
and the sign-on message will be different for the new ROM's. 

Radio Shack has made some welcome changes too. The 
first, and most needed, was the switch to a new type of 
keyboard that doesn't bounce (produce extra letters every 
time a key is pressed). Another change involving the key- 
board, was the addition of a numerical keypad. That is par- 
ticularly useful if a lot of numbers are going to be entered. 
It comes free on new computers. You can add it to older 
units, that didn't come with it. for $99. 

Another hardware modification now available is a lower- 

Icase adapter. That board, which plugs into the keyboard 
unit, costs $99 and allows you to display lower-case letters 
on the video monitor. 




VOICE SYNTHESIZER adds speech capability to the computer. 




ECONOMICAL Quick Printer II uses electrosensKlve paper. 

For business applications, consider the Model II 

In May 1979, Radio Shack decided to make a concen- 
trated effort to capture a large part of the business-com- 
puter market and introduced the vehicle it was going to use 
to do that — the TRS-80 Model II. In its most basic config- 
uration, the Model II comes with 32K of RAM and a single, 
built-in, 8-inch floppy-disk drive. The cost of that system 
ts $3450. The processor used is a Z80A, which is a 4-MHz 
version of the processor used in the Model I, It is possible 
to add on an additional 32K of RAM for another $449. 

While the basic computer comes with only one disk drive 
with 500K of on-line storage, that can be expanded to two 
megabytes of on-line storage by adding three more disk 
drives at a cost of $2350. 

Radio Shack calls the BASIC it provides with the Model 
II Level III BASIC; that can be confusing, because Micro- 
soft sells what it calls Level III BASIC for the Model I, 
and the two are not the same. Radio Shack's Level III 
BASIC is almost identical to the Level II BASIC— there are 
some exceptions. The BASIC in the Model II has 23 more 
commands than the BASIC in the Model I machine. A list 
of the commands in both BASIC'S is shown in Table I. while 
those added to Level III BASIC are shown in Table II. 
What is not shown on those tables is a serious omission in 
Level III BASIC, in which the peek and poke and inp and 
OUT commands from Level II BASIC are no longer avail- 
able. Radio Shack claims that those commands are no longer 
needed, but already several companies are advertising short 
little machine-language programs for sale that restore the 
peek and poke commands to Level III BASIC. 

There are some differences in the DOS (Disk-Operating 
System) on the Model II as well. The principal one is that 
the DOS responds with positive feedback. If, for example, 
you tell the computer to "KILL 'file name'", the computer 
will respond with "'file name' KILLED" or '"file name* 
NOT FOUND", so you always know what is happening. 
In addition, when duplicating a diskette, it is necessary to 
know the master password. 

There is a huge variety of equipment and accessories for 
the TRS-80. So before you go any further you really want to 
gel a copy of the Radio Shack Computer Catalog. R-E 



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A Few Extraordinary Products for Your 6800/6809 Computer 

From Percom . . . 

Low Cost 
Mini-Disk Storage 
in the Size You Want 



illill!4 
fill III l» 

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Percom mini-disk systems start as 
low as $599.95, ready to plug in and 
run. You can't get better quality or a 
broader selection of disk software 
from any other microcomputer disk 
system manufacturer — at any price ! 

Features: 1 -, 2- and 3-d rive systems 
in 40- and 77-track versions store 
102K- to 591K-bytes of random ac- 
cess data on-line ■ controllers in- 
clude explicit ciock/data separation 
circuit, motor inactivity time-out cir- 



cuit, buffered control lines and other 
mature design concepts • ROM 
DOS included with SS-50 bus ver- 
sion — optional DOSs for EXOR- 
ciser* bus * extra PROM sockets 
on-board • EXORciser* bus version 
has 1 K-byte RAM - supported by ex- 
tended disk operating systems; as- 
semblers and other program de- 
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--> 



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Versatile Mother Board. Full-Feature Prototyping Boards 

Printed wiring is easily sotdered (in-lead plugged into an SS-50 bus. Features 
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bus connectors, other connectors and SS-30 BUS CARD — 1V<-inch higher 
sockets are optional. than SWTP I/O card, accommodates 34- 

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The SBC/9™. A "10" By Any Measure. 

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™ trademark ol Percom Data Company. Inc. 

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Prices and specifications subject to change without notice. 



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True baseline descenders. 

• Character-store (display) 
memory included on card 

• Provision for optional 
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EPROM for user defined 
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• Comprehensive users 
manual includes source 
listing of Driver software. 
Driver — called WINDEX™ 
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50 



CIRCLE 75 ON FREE INFORMATION CARD 






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Commodore's PET was the first all-in- 
one personal computer. Since its 
introduction it has undergone many 
changes. The toy has evolved into a 
business machine. 



COLUMNS 








IF THERE IS ONE COMPANY THAT IS RESPONSIBLE FOR THE 

personal computer revolution and the development of plug- 
it-in-out-of-the-box computers, it is Commodore Business 
Machines. And if there is one person that is responsible 
for it, his name is Chuck Peddle: It was he who had the 
foresight to realize that what the world needed was a 
ready-to-use home computer that didn't have to be assem- 
bled. And the first company to announce such a computer 
was Commodore. 

When the first news articles on the PET computer 
appeared in the technical press five years ago, it seemed 
too good to be true. They described a full-blown computer 
with a CRT display and an ASCII keyboard for only $600. 
Oh, sure — there were a lot of computer kits available at 
that time for about the same price; but none of them had 
the same capability. 

The kits gave you a CPU, power supply, and a box to 
house it in. One or two manufacturers even offered some 
memory. But you, the purchaser, still had to toil long hours 
to build and debug the unit — and after that you still couldn't 
use it, because it required a host of peripheral interfaces 
and, of course, an I/O device, such as a teletypewriter. 

Then came the announcement from Commodore that 
they were going to supply the entire thing, assembled and 
ready to run BASIC at the flick of a switch. And all that 
would cost less than most of the basic kits. Along the way, 
the $600 PET fell by the wayside, as did most of the Do-It- 
Yourself computer kits. The 4K. PET gave way to the 8K 
PET, and the cost went up to $800, but it was still a bar- 
gain. Seeing the interest that was generated by that ready- 
to-use computer, it didn't take long for other manufacturers 
to jump on the bandwagon. 

But look at that keyboard! 

One of the most controversial aspects of the PET that 
was first announced was its keyboard. It consisted of 73 
keys that were arranged in an ASCII block of 53 keys and 
a 20-key numeric and control key block. Unlike the key- 
boards on its subsequent competitors, those on the PET 



were made with calculator-type pushbuttons. The keys 
were not arranged in the standard staggered configuration 
found on typewriters and they were also considerably 
smaller than typewriter keys. All of that led to complaints 
about the keyboard and how it wasn't possible to touch- 
type with it. While most of those complaints were probably 
justified, as evidenced by the fact thai eventually Com- 
modore came out with a PET that had a standard-sized 
keyboard, at the time the issue was really insignificant. 
Here was a company that was offering a complete com- 
puter system for only $800, a price that only two years 
before would have been scoffed at. The complaint, how- 
ever, was a good way for Commodore's competitors to 
make points, and so the controversy raged. 

Another advance from Commodore, that was related 
to the keyboard, was that the PET was the only computer 
to offer the full upper and lower case ASCII character set, 
64 graphics character and 1 1 special function keys. Among 
those "special function" keys was a key to enter the value 
of the math constant (pi) x ; keys to control the cursor (up, 
down, left, and right); a key to clear the screen and home 
the cursor: a key to insert and delete data; a reverse field 
key, and even a key to cause a program to be loaded auto- 
matically and run, or to stop program execution. In addition, 
a slow-list capability was provided by holding down the rvs 
key while a program was listed. 

Getting physical 

For those of you who never saw the original PET, discon- 
tinued last year, here is a quick description of it. It is a one- 
piece factory-assembled computer that weighs 44 pounds and 
measures 14 inches high by 16.5 inches across, and is 18.5 
inches deep. It has a built-in 9-inch CRT display and a built- 
in semiautomatic tape-storage system. I call it semiautomatic 
because the user must place it in the record or play 
mode, and it does not automatically fast forward or 
REVERSE. However, the integral file-handling system that 
is built into the PET does tell the user which mode to place 
the recorder in (and when) and it does start and stop the 



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tape automatically under computer control. 

Last year. Commodore succumbed to the pressure it 
was receiving from users and came out with a new version 
of the PET that had a full-sized keyboard. It is housed in 
the same case as the original PET, so its dimensions are the 
same, but because the keyboard is much larger, the tape 
recorder had to be made an external accessory, and to get 
it you had to pay an extra $95. The new keyboard has 
added some features that were sorely lacking in the early 
PET computers. To begin with, it contains a SHIFT LOCK 
key. But why should the lack of a shift lock key be 
considered such a big disadvantage for the PET> After 
all, many other computer keyboards don't give you this 
function either. That's true, but most other computers 
also do not provide the wide selection of characters that 
are available on the PET. And the lack of a shift lock 
was very annoying whenever a lot of graphics or lower- 
case letters were being entered. 

When the new keyboard was added, the motherboard 
inside the computer was redesigned so that up to 32K. of 
dynamic memory could be used. In the original PETs. 
expansion had to be done externally. Also, static memory 
was used; it's easier to design with, because no refresh 
circuitry has to be included, but it generates a lot of 
heat. In addition, MOS Technology, a subsidiary of Com- 
modore, was the only company that made the memory 
IC's, and as a result, replacements were very expensive. 

With the addition of the new keyboard. Commodore 
decided that it would increase the basic machine from an 
8K machine to a I6K machine, since most people wanted 
more memory anyway. The base price of the new PET 
was also raised, by 5200, and it now costs $995 (plus the cas- 
sette recorder). The price for a 32K machine, which is identical 
in every way to the 16K machine except for the extra 
memory, is $1295. That means you're paying $300 for 16K of 
RAM. an outrageous price. 

When it first came out, perhaps one of the biggest selling 
points, aside from price, was the PETs ability to "speak" 
BASIC as soon as it was turned on. That's fairly common 
today, but four years ago it was a real innovation. 

Another handy feature that was (and still is) found in 
PET computers, is a very good screen editor that makes 
it easy to correct mistakes. With the editor, you can move 
the cursor wherever you want to on the screen and then 
insert or delete characters or whole words with no difficulty. 
And, unlike the case with other screen editors, you do not 
have to re-enter the entire line that is being corrected. All 
you do is to make your correction and then press return; 



the computer automatically enters the corrected line. 

It has a file system, too 

As mentioned earlier, the PET is capable of reading and 
writing programs and data files to cassette tapes. The tape 
recorders used cost $95 each, which is about two to three 
times the price of a decent cassette recorder that can be 
used with most other computer systems. Although the 
tape unit uses a commercial audio-cassette drive mecha- 
nism, the electronics are custom-made so that only that 
special recorder can be used. I have heard however of a 
company that sells an adapter, which will permit you to 
use a conventional cassette recorder with a PET, but I 
haven't seen it. And with such an important task to per- 
form, it's probably better to pay the extra money — or 
better yet, go to a disk-based system. 

The tape system in the PET is very reliable. The system 
records data at 1000 baud, which at first glance makes one 
think that it is rather fast. However, to insure data relia- 
bility, it records everything twice, and when it reads back 
data, it reads both recorded versions to verify that what 
it has read is correct. Thus the effective baud rate is only 
500 baud, the same as the TRS-80 Level II. 

Unlike other tape systems which require low-noise 
tapes and meticulous adjustment of volume-control levels, 
the PET system can use just about any kind of tape, and 
no adjustments whatsoever are needed. I have tried a wide 
variety of tapes and found that even the cheapest kind 
available can be used successfully. 

A handy feature of the tape system {missing from some 
of the popular systems) is the VERIFY command. After 
using it. I can't see how any computer can be without it. 
That nifty little command allows you to check and see if 
the program you recorded on tape was recorded without 
errors. I have yet to find a program that wasn't recorded 
properly. 

In systems without that feature, notably the Apple, the 
only way to check whether the program was recorded 
properly is to load it into the computer. But that destroys 
the original program that is in the machine; so if your tape 
has dropouts on it, or the battery voltage of your tape re- 
corder is low. loading the defectively-recorded program 
into your computer will wipe out the original program, and 
several hours worth of work can go down the drain. 

Another plus for the PET tape system is that it works 
with named files. That means that you can give each pro- 
gram or data file a name, which is stored on the tape as a 
program header. Then you can tell the computer to load a 
program with a particular name, and it will ignore all others 
on the tape and only load the one with the desired name. 

Commodore designers have made the PET a little more 
personal by including routines that keep the user posted 
about what is going on. For example, while it is looking for 
a particular file, the computer will let you know, not only 
that it is making the search, but it will also tell you which 
files it has passed on the tape while it was looking for the 



one that you specified. That makes the PET more useful. 
About the only thing that is missing in the way of basic 
features, is the ability to use the bell feature (ASCII 
character 7) of the ASCII keyboard. 

Thanks for the memory 

When it first came out. the least expensive version of 
the PET was the 4K system, which sold for $595 and offered 
the user 4000 words (each digital word represents one 
character) of random-access memory (RAM). But that 
wasn't all — you also got 14K of read-only memory (ROM). 
which contained an 8K BASIC interpreter, a 4K operating 
system, a IK monitor program, and a IK diagnostic pro- 
gram. It was the 14K of ROM that put the PET way ahead 
of all other systems on the market at that time. Now most 
personal computers have similar features. 

Since the PET was first introduced, the system ROM's 
have undergone several revisions. The original ROM's had 
a bug in them that would occasionally cause the cursor 
to be lost. That would require that the computer be shut 
off and turned on again in order to recover. Obviously, 
any program in the computer would be lost. Commodore 
acknowledged that bug and replaced the defective part 
free to anyone who reported problems. The next set of 
ROM's to be made available were the new ones that were 
developed for the I6K and 32K PET's. That was not just a 
simple replacement of a single ROM. but an entirely new 
set. The changes in those ROM's are many and most of 
the machine-language routines have been shifted around 
so that programs using machine language calls from the 
original ROM set cannot be used without modification on 
the new set. Commodore is now about to announce an 
even newer ROM set, BASIC 4. which makes interfacing 
to the disk drive a lot easier. That set was originally devel- 
oped for the latest computer to be added to the Commodore 
tine, the 80-column CBM computer. And still another ROM 
set is in development, this one called BASIC 5. This ROM 
set will have a lot of utilities built into it such as renumber, 
append, and many others. The BASIC also includes an 
additional command called protect, which, when in- 
voked, prevents the user from accessing the source code 
or making a copy of the program. 

While many people complain about the frequent and 
incompatible ROM changes. I see it as a good point for the 
Commodore computers. It shows that Commodore is con- 
stantly seeking to improve their products, which is really 
nice to see. 

New 80-column computer available 

Recently, Commodore has announced a new computer, 
aimed squarely at the business market. Known as the 
model 8032 CBM computer, it features a 12-inch CRT and 
a full business keyboard with numeric keypad. The BASIC 
in the 8032 is Commodore's latest — version 4,0 — and it 
works with the new disk-operating system. DOS 2.0. The 
new BASIC corrects several errors in the previous basic 
and adds some enhancements. 

Externally, the 8032 is similar to the 16K/32K PETs, 
except that the shape of the cabinet has been changed 
slightly to accommodate the larger video monitor. Included 
in the 8032 is an electronic bell that can be accessed via 
ASCII character 7. In addition, the bell is used as an end- 
of-line warning device, much like the bell on a typewriter. 
It sounds when the cursor passes column 75 on the screen. 

PET checks itself out 

From the repair point of view, the PET is a serviceman's 
dream. For the old PET's. with the aid of a special con- 
nector, the PET can check itself out. Once the source of 
a fault has been located, repairing the system is simple. 
Each of the three boards can be snapped out quickly and 
replaced with another, so that the system can be up and 



running in no time. For the new PET's, Commodore has a 
special boot-strap loader that clips onto the 6502 micro- 
processor chip and loads in the diagnostic program. The 
reason that is necessary is that the new ROM's have no 
room for the diagnostic routines. Once the diagnostic pro- 
gram is loaded, servicing is as before. 

Microsoft BASIC is used 

The BASIC that is in. the PET ROM's is a Microsoft BASIC 
and as such is fairly compatible with the BASIC'S that are 
found in most home computers. Of course it contains the 
PEEK and POKE commands that have become popular 
with the .microcomputer revolution. In addition, it contains 
some special commands that are designed specifically for 
use with the IEEE bus. 

Also part of the repertoire are tape-file handling com- 
mands, such as OPEN, input*, print* and CLOSE. 
PET BASIC also contains a GET command that inputs a 
single character from the keyboard without printing it, 
making it possible to hit the return button without 
stopping the program. 

PET BASIC has one more very useful command: ti. 
That is not an oblique reference to one of Commodore's 
competitors, but rather a time command; it's used in con- 
junction with the PETs built-in clock. It can be used to 
time programs or even set up a lime-of-day program in the 
computer. 

Plenty of peripherals are available 

In the way of mass storage. Commodore has two-disk 
systems announced and a few more on the way. The first 
is the 2040 dual-drive minifloppy system. It uses Shugart 
390 drives and the system is accessed in the same way as 
the cassette-operating system. 

The 2040 costs $1295, has access to 340K of data on the 
two drives, and it doesn't use double density and double 
tracking techniques. The density is achieved by using two 
microprocessors (a 6502 and a 6504) and five memory IC's 
that are built into the disc unit itself. But the real key to 
the high density is an encoding scheme that packs the data 
so that less storage space is needed. 

The information needed for encoding data to be stored on 
the disk is contained in 2K of ROM located in the disk 
unit. Also included is an 8K ROM-based disk-operating sys- 
tem. In addition, the 2040 contains 4K of static RAM. 

Only two connections are needed for the disk system; 
an AC power cord to supply it with 50 watts of power and 
an IEEE interface cable to connect it to the PET. The 
diskette itself is a soft-sectored one that is formatted by the 
drive. It has 35 tracks, with a constant recording density. 
The number of sectors-per-track, however, varies — from 

17 for the innermost tracks to 21 for the outermost. Track 

18 of the diskette is used for the directory of programs that 
are on the disc. 

For those who require even more data-storage capability. 
Commodore has just announced a new dual-disk drive 
system known as the 8050, That system provides three 
times the storage capability— 5 12 kilobytes-per-diskette or 
1 megabyte-per-dual-d rive- system — for only t/3 more 
money ($1695). 

In the area of hard copy. Commodore has two printers. 
One is the CBM 2023, which is a matrix, impact printer that 
has a pressure feed and takes 10-inch-wide roll paper. It 
prints at 80 characters per second and costs $695. The 
second printer, the CBM 2022 is similar to the 2023. except 
that it is a tractor version and costs $100 more. Both 
printers connect to the PET Via, the IEEE bus. 

Commodore has two more peripherals available that 
may be of interest: a voice synthesizer for $395 and an 
acoustically coupled modem for $395. The modem is a half- 
and full-duplex modem that features asynchronous oper- 
ation at 300 baud. R-E 



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The first Apple computer was the brainchild of two 

young men working out of a garage. The young men 

are now rich, and the Apple a resounding success. 






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ONE OF THE VETERANS OF THE PERSONAL-COMPUTER REVO- 

iution is Apple Computer Company. In 1975, when micro- 
computers first appeared on the scene, Apple Computer was 
the first company to offer a single-board computer. The price, 
for what was then known as the Apple I. was $666. That in- 
cluded an onboard ROM monitor and a built-in video interface. 

About eight months after the Apple I appeared on the 
market, the Cadillac of home computers made its debut. 
Apple II. The Apple II represented a giant step forward in 
home computing then and, except for its newly introduced 
brother, the Apple III, it is still the best buy in personal com- 
puters around. 

Like its predecessor, the Apple II has built-in video cir- 
cuitry that allows it to interface directly to a color- video 
monitor, or to a television set through an add-on modulator. 
Apple II's now come in two varieties, the Apple II and the 
Apple II Plus (often refeired to as minus by experienced 
Apple owners). The difference between the two machines is 
in the BASIC that you'll find resident in the computer at the 
time of purchase. 

On the Apple IT, the computer comes with Integer BASIC 
resident in ROM. The term "integer" refers to the way the 
computer performs mathematical operations. In Integer 
BASIC, for example, 5-^2 would yield 2 instead of the ex- 
pected 2,5, because 2.5 is not an integer. While that seems 
strange and hardly useful, such is not at all the case. Integer 
BASIC is very fast and as a result lends intself well to ap- 
plication in games programs. 

For those who wish to have the floating-point capability 
(where in the above example you'd actually get 2.5) it is pos- 
sible to purchase an additional firmware board with Apple- 
soft BASIC in it: that is the BASIC that is available on most 
computers. In addition, older Apple systems were supplied 
with Applesoft on disk so that those with a lot of memory 
and an integer machine could have Applesoft available to 
them. 

The second type of Apple, the Apple II Plus, comes with 
Applesoft as the BASIC that is resident in ROM in the ma- 
chine. When Apple Computer Co. made this version of the 
computer available, they also changed one of the system 
ROM's to add some additional features. Unfortunately, 
when something is added, something else must always be 
taken away and in that case it was the built-in mini as- 
sembler. Also, Apple Computer Co. decided to give the 
system the capability of being a turn-key system so that pro- 
grams could be run as soon as power was applied, if a disk 
drive were used. Finally, the reset circuitry was modified 
so that it was software-controllable. All of those features 



have pluses and minuses, but owners of the Plus see only 
the minuses, hence the nickname. By the way, all of the 
features taken away from the Apple II Plus are restored to 
the computer when the Integer firmware card is installed. 

The low end Apple II, be it the regular or the Plus, contains 
16K of random-access memory and has sockets that allow 
the user to expand it to 48K just by plugging in the extra 
IC's. The I6K Apple lists for $1200, but can be gotten, by 
carefully examining the ads in computer magazines, for as low 
as $950. For that price you get one type of BASIC, a built-in 
speaker, a standard 52-key typewriter-quality keyboard, an 
8-stot expansion bus that is widely supported by independent 
manufacturers, a built-in video interface, two paddles for 
interactive games, four built-in analog-to-digital converters, 
a variety of demonstration programs, and a machine that will 
give you hours of fun. The built-in speaker can be used to 
produce music, warning 'beeps', or even play back digitized 
speech. 

Five display modes available 

The computer has five display modes. The first, and most 
frequently used, is the all-text display mode. Then there are 
two low-resolution, full-color graphics display modes: one 
that combines the 40-x^IO low-resolution graphics with four 
lines of text and the other that is all graphics. The same holds 
true for the high -resolution graphics mode. There is one that 
permits four lines of text on the bottom of the screen and the 
plotting of points on a grid 280 wide x 160 high. In the all 
graphics mode the resolution increases to 280 x 192. There 
are six colors available in the high-resolution mode, including 
black and white. The resolution in that graphics mode is so 
fine that it ts possible for the user to define his own character 
set, Apple Computer has a program in its contributors library 




APPLE II DISK DRIVE uses uniquely-designed controller card. 










INFORMATION UTILITIES, discussed elsewhere in this section, are easily 
accessed by the Apple II. 



that does just that and several software companies sell pro- 
grams that do it too. 

Those character-generator programs are popular, because 
the Apple II has no built-in capability to display lower- 
case letters. Several independent manufactures, such as 
Mountain Hardware and Dan Paymar, have overcome that 
problem with accessory devices, the cheapest of which is the 
Paymar adaptor for only $50. One hardware limitation of the 
Apple II is that it only displays lines of 40 characters. Here 
again, outside manufacturers have been innovative and come 
up with accessories that increase that to 80 characters per 
line, but in those cases, the computer must be used with a 
video monitor. 

In the text-display mode, the Apple II has programmable 
text windows, so it is possible to divide the screen up into 
several distinct sections and access any one of them under 
program control while the others stay fixed. Each window 
has its own scrolling capability, and each can be cleared 
individually, In addition, characters on the Apple II can be 
displayed in one of three modes. The first — and most often 
used — is the normal white-on-black display. The next is an 
inverse mode where letters are displayed black on white. 
Finally, they can be displayed in a flashing mode. Using 
Applesoft BASIC, it is simplv necessary to invoke the 
NORMAL, INVERSE or FLASH commands to display 
the text appropriately. In Integer BASIC the same things can 
be accomplished by POKEing a particular location in memory 
with various values. That versatility in handling text makes it 
possible to produce interactive programs that are both at- 
tractive and easy to read. 

In addition to the main computer unit, Apple has several 
accessories available for it. The most important is a disk 



drive. Apple disk drives cost $495 if purchased from Apple 
Computer and $395 if a compatible drive is purchased from 
an independent manufacturer. The drive -controller card, 
which can handle two drives, sells for $100. Apple has done 
some pretty innovative things with their disk system. They 
use the standard SA400 drive from Shugart, but they don't 
use the Shugart digital controller card that comes with the 
drive. Instead, they replace it with their own. Aside from 
reducing the parts count on the card, which increases re- 
liability, they've made the card smart, so that it can cal- 
culate the acceleration and deceleration of the drive and 
compensate for it when accessing the disk. 

The standard Apple disk drive is capable of storing I !6 
kilobytes of data. However, Apple has developed two new 
ROM's for its controller card which make it possible to in- 
crease storage to 143 kilobytes per diskette, and that up- 
grade kit, along with a new version of DOS (Disk Operating 
System) to support it (DOS 3.3) should be available by the 
time you read this article. 

It understands Pascal too 

Apple Computer Co, is quick to recognize desires of the 
public and when it became apparent that the computer 
language Pascal was becoming popular, it set about develop- 
ing a method of implementing it on the Apple II. As a result, 
about a year ago, Apple came out with an accessory known 
as the Language System. That $500 system makes it possible 
to run the popular UCSD Pascal language on the Apple II 
computer. 



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THE WHOLE COMPUTER weighs only seventeen pounds. 

The Language System consists of a card that plugs into 
one of the slots in the Apple. The card contains an extra I6K 
of RAM, support circuitry, and a ROM that will permit the 
Apple disk to boot up automatically when power is applied. 
A reasonable price for the board alone would be $100 to $ 150. 
The extra money for the system is for the software that 
comes with it, the UCSD Pascal system which includes an 
editor, compiler, linker, and utility programs. The system 
also includes a 6502 assembler. Finally, two ROM's are in- 
cluded, which must be used to replace ROM's that are on 
the standard disk-controller card. Those ROM's set up the 
disk drive to work with 16-sector disks, as opposed to the 
standard 13-sector ones. The increase in sectors accounts 
for the increase in density from 1 16K to 143K that is asso- 
ciated with the Language System. 

Although the Language System is commonly referred to as 
the Pascal card, that is really not accurate since Apple is 
planning on having other languages available for it soon. 
Already announced are FORTRAN and Pilot. 

Apple III is coming 

In May of this year, Apple Computer Co. introduced its 
next-generation computer, the Apple HI, which should be on 
your dealer's shelf by the time you read this article. Basical- 
ly, the Apple III has everything Apple II owners wished they 
had in theirs and went out and bought accessories for. The 
Apple III has a built-in mini-disk drive; printer interfaces for 
serial and parallel printers; a real-time battery-powered 
clock-calendar that will run for three years and keep track of 
time to within 1 ms; standard IBM keyboard with a numeric 
key pad with automatic repeat of any key, a 2-inch speaker, a 
fixed frequency 'beep' generator, a 1-bit squarewave genera- 
tor, and a 6-bit digital-to-analog converter. The basic unit 
comes with 96K of memory; that is expandable to 128K. 






THE NEW APPLE III, aimed primarily at ttw business marVat 

Like the Apple II, it uses a 6502 microprocessor, but it has 
been enhanced in two ways. Firstly, a 2-MHz version of the 
CPU (known as the 6502A) is used. That immediately makes 
the Apple II two times faster. Secondly, external logic has 
been added to enhance the 6502 instruction set. Additional 
CPU features include a relocatable base-page register and a 
relocatable stack. 

A nice feature of the new computer is that the character 
generator is stored in RAM. That means that all characters 
are software-defineable and that any type font can be gener- 
ated. So, in addition to defining new character sets, such as 
Greek and Hebrew, it is possible to generate high-resolution 
figures in the text mode. Another result of that is that scrolling 
can occur one dot row at a time, resulting in a smooth, non- 
jerky movement. 

Perhaps the smartest feature of the Apple III is its built- 
in Apple II emulator. When activated, that makes the Apple 
III look exactly like an Apple II, and all the software that is 
available for the Apple II will work on it. The Apple HI also 
has a Language System built in and is thus capable of running 
Pascal as well. 

Support is the best around 

When it comes to helping out a customer or dealing with a 
problem, be it malfunctioning equipment or answering tech- 
nical questions, Apple's support is the best around. Apple's 
network of service centers is geared to repairing or replacing 
defective parts within 24 hours. While that goal isn't always 
achieved, their track record is pretty good. And if you've got 
a technical question, Apple's hot line (408-996-9868) is al- 
ways staffed during the business day to provide customers 
the answer to any question, be it hardware-or software- 
related. 

Having used that hot line quite a bit, I can tell you first 
hand that it is great; the people manning it are both patient 
and helpful. If they don't know the answer, they'll find 
someone who does. The only problem with the hot line is. 
that it is only manned by two people at a time with only two 
telephones; thus getting through can be difficult at times. 
No other manufacturer, though, has anything better. 

The Apple's popularity extends around the world, and the 
software and hardware support for it are almost beyond 
belief. Many games, programs and peripherals first developed 
for it have been adapted for other systems. It's no wonder 
that the Apple has become one of the top-selling personal 
computers! R-E 





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These products provide one of the least 
expensive ways of building up a system. 



OHIO SCIENTIFIC. INCOROSI. WAS ONEOFTHE EARLY ENTRIES 

in the home computer market, dating back to the Lk old" 
days of 1975. Their present line of computers ranges from 
simple one-board computers to sophisticated rack-mounted 
computers and consists of four product lines; the Chal- 
lenger I, Challenger III, Challenger 4 and Challenger 8, 

The Challenger I series, which includes several models, 
is aimed at the student and hobbyist with prices ranging 
from $279 to $995. For the higher performance needs of 
the professional and educational user, there are several 
models in the Challenger 4 and Challenger 8 series that 
range from $698 to $2597 price bracket. The small-business 
computer series. Challenger III, starts above $4000 and 
will not be detailed here. A comparison chart detailing the 
key features appears in Table 1 . 

Beginners can start "naked" 

The first member of the OS I family of personal micro- 
computers is the Superboard 11, a "naked" microcom- 
puter, without power supply (5 volts at 3 amps required) 
and cabinet. The Superboard II includes a full 53-key ASCII 
character keyboard, a 30-row by 30-column video-display 
interface for use on a video monitor or home television 
via an RF modulator, and a cassette tape interface that 
will work with most home cassette recorders. Also included 
on the board is an 8K BASIC in ROM and 4K or 8K of 
RAM. 

The Superboard II is directed toward the computer neo- 
phyte who can start getting into this fascinating hobby with 
an inexpensive basic system that works reasonably well 
and can be expanded to include other peripherals such as 
a floppy disk drive. The Superboard 11 with 4K of memory 



costs $279 while the 8K version costs $348. 

Add a power supply and an enclosure to the 8K Super- 
board II, and it becomes a Challenger CI P. designed to be 
used with a standard television set (via a separate RF video 
modulator). An optional 12-inch OS I black-and-white video 
monitor is available for another $115. The Challenger CIP 
offers upper and lower case characters from the keyboard. 
On the video screen, it will display up to 30 lines of 30 
characters each in the text mode. In the high-resolution 
graphics mode, it will display dots within a 256-by-256 
grid. 

As is the case with most of the popular personal com- 
puters, except for the TRS-80, the OSI computers use 
the 8-bit 6502 microprocessor. The bare-bones Challenger 
CIP, without the audio cassette recorder and without the 
video monitor, is $399. 

The next step up is the Challenger CIP MF which includes 
I2K of RAM. the 8K BASIC in ROM, and either one or 
two 5-1/4-inch mini-floppy disk drives. With disk drives, 
data retrieval can be achieved in seconds rather than the 
minutes required when a cassette storage system is used. 
The cost of a CIP MI' with 12K of RAM, the 8K ROM 
BASIC, and one mini-floppy disk drive is only $995. That 
price makes it the cheapest disk-based personal computer 
available anywhere. Need more memory? The CIP MF 
can be expanded up to a total of 32K of RAM. With 20K or 
more of memory, small-business applications can be 
handled through OSI's powerful OS-65D V3.0 operating 
system that supports sequential as well as random access 
data files directly from BASIC. 

Peripherals available for the Challenger CIP MF include 
an electrostatic or impact printer ($695 and $1250 respec- 



TABLE I 



Feature 


Superboard 


C1P 


CtPMF 


C4P 


C4PMF 


C8P 


CBPMF 


Min. RAM 
Max. RAM 
Base Price ($) 


4K 
8K 
279 


8K 
8K 
399 


12K 
32K 
995 


8K 
32K 
698 


24K 
48K 
1695 


8K 
32K 
895 


32K 
48K 
2597 


Color Graphics 
Joystick Int. 
Keypad Int. 


No 
No 
No 


No 
No 
No 


No 
No 
No 


Yes 
Yes 
Yes 


Yes 
Yes 
Yes 


Yes 
Yes 
Yes 


Yes 

Yes 
Yes 


AC Remote Int. 
Modem Interface 
Printer Int. 


No 
Opt 
Opt 


No 
Opt 
Opt 


Opt 
Opt 
Opt 


Yes 
Yes 
Yes 


Yes 
Yes 
Yes 


Yes 
Yes 
Yes 


Yes 
Yes 
Yes 


Home Security 
Audio Output 
O/A Converter 


No 
No 
No 


No 
No 
No 


No 
No 
No 


No 
Yes 
Yes 


Yes 
Yes 
Yes 


No 
Yes 
Yes 


Yes 
Yes 
Yes 


Video Display 
Real Time Clock 
GT Option 


30x30 
No 
No 


30x30 
No 
No 


30x30 
Yes 
No 


32x64 
No 
No 


32x64 
Yes 
Opt 


32x64 
No 
No 


32x64 
Yes 
Opt 






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lively), a 300-baud modem ($199), and a home controller 
($175). The AC Remote Control System, or home control- 
ler, together with a real-time clock, enables the computer 
to operate lights and appliances automatically under pro- 
gram control. The AC-controi interface permits the com- 
puter system to inject control signals on the AC power line 
circulating throughout the home, and turn lamps or appli- 
ances on and off. Also available is a home security system, 
including smoke and door/window burglar-alarm sensors. 
Should an entry be attempted, or smoke be present, the 
computer would be informed immediately, and the appro- 
priate devices would be activated. 

Do rt better with a C4P 

The Challenger C4P is a cassette-based system and in- 
cludes the 8K ROM BASIC, just like the CIP. But the C4P 
has some additional features. It has over three times the 
display capability of the CIP and is capable of displaying 
32 lines of 64 characters each, in up to 16 colors. In the 
graphics mode, the screen resolution is 256-by-5 1 2 points. 

Also included in the C4P is a 200-Hz to 20-kHz program- 
mable tone generator, an 8-bit companding digital-to-analog 
converter (DAC) for voice and music generation, two 8- 
axis joystick interfaces for interactive games, two 10-key 
keypad interfaces, and an AC remote-control interface 
for appliance and home control systems. The basic C4P, 
selling for $698, may be expanded to hold up to 32K of 
RAM through the use of two expansion slots in the key- 
board chassis. The RAM used in the computer is all static and 
therefore requires no system refreshing; it can easily 
be backed up using a battery supply. With as little as 24K 
of RAM. the C4P will handle 5-1/4 inch mini-floppy disk 
drives which cost $450 each. 

If you decide in advance that mini-floppies are the way 
to go, then the CAP MF, at $1695, provides the same fea- 
tures as the C4P but includes 24K of RAM and a single 
mini-floppy disk drive. In addition, the C4P MF contains a 
real-time clock and countdown timer, a modem interface, 
16 parallel lines for additional control interfaces, an acces- 
sory bus for an external 48-line I/O board, and a home- 
security system interface. The system can be expanded 
to 48 K of RAM and two mini-floppies. 

The computer features a "foreground-background" 
capability that allows it to monitor a home-security system 
and turn appliances on and off white at the same time it 
is running another application program. The C4P MF is the 
only home computer that has that capability built into it. 



According to Ohio Scientific, the C4P MF normally 
operates twice as fast as an Apple II or PET and three 
times faster than a TRS-80. However, if you need even 
more speed, it is possible to double that speed by getting 
the GT option, which is a special ion-implanted 6502, along 
with faster RAM. The option can only be ordered at the 
time of purchase and costs an extra $950. 

For more expandability try the C8P 

The top-of-fhe-line in personal computers for Ohio Scien- 
tific is its Challenger C8P series of computers. The C8P 
contains eight expansion slots, only five of which are available 
to the user. The others are used for the basic configuration. 
That means that the C8P has more than three time the expan- 
sion capability of the C4P . The basic C8P is a cassette- 
based machine with 8K BASIC in ROM and 8K of static 
RAM. That can be expanded up to 48K of RAM. To in- 
crease program storage, the C8P can be interfaced to two 
8-inch floppy disk drives. The basic C8P costs $895 with 
8K of RAM. 

If you need more memory, it can be upgraded to a C8P 
DF, which costs $2597. That gives you 32K of RAM (ex- 
pandable to 48K) with dual 8-inch floppy disk drives that 
are capable of storing up to 250 kilobytes of data. The C8P 
DF offers the same features as the C8P plus the Home- 
Security System. An optional Universal Telephone Inter- 
face can dial any telephone number via rotary dial or Touch- 
Tone (TM) techniques. By combining the Universal Tele- 
phone Interface with OSI's Votrax voice I/O board here's 
what you'll get: A computer system that can dial any num- 
ber and communicate via voice output, leaving messages, 
and answering anticipated questions. Add to that combin- 
ation the home-security system, and the C8P DF can auto- 
matically dial the police or fire department, and by voice 
message commuicate its emergency needs. A dedicated 
alarm dialler, however, would probably be more cost ef- 
fective. Another possibility is that the computer owner 
can dial home from some remote location and tell the com- 
puter to turn specific appliances on and off. 

Like the C4P, a GT option is available for the C8P DF 
too. If desired, it must be ordered at the time of purchase 
and costs an extra $1825. 

Software, including Pascal and FORTRAN for 48 K sys- 
tems with at least two mini-floppies, for the Ohio Scientific 
computers is available on both tape and diskette, with prices 
ranging from $6 to $200. R-E 




Originally, all personal computers were available 
only as kits. Now, just the opposite is true. 
Heath, though, still lets you build your own. 



IT'S NOT EASY TO LOCATE A PERSONAL COMPUTER SYSTEM 

that includes a smart terminal plus a floppy disk for under 
$2000, But. if you are familiar with basic electronic kit 
assembly and construction, you can buy a relatively sophis- 
ticated computer that uses not one but two Z-80 micropro- 
cessors, a smart video terminal, 16K of random access 
memory (RAM), and a I00K minifloppy-disk storage sys- 
tem. All of that will cost you only $1695. And with a rea- 
sonable degree of patience and confidence, it will work 
when first turned on. 

When personal computers first appeared five years ago, 
almost all were kits. Today it is just the opposite: almost 
all are assembled and ready to use. But Heathkits have 
always been popular and have a reputation for working well 
the first time. Nonetheless, if kits don't "turn you on," 
you can still enjoy the Heath computer by purchasing a 
WM89 (W for wired) All-in-One computer, factory-assem- 
bled and tested. Whichever model you get, the H89 is a 
fully integrated desktop computer with many built-in fea- 
tures plus a wide variety of external peripherals available. 

The 8-bit H89 includes a computer, 12-inch black-and- 
white video display, 5W-inch minifloppy-disk drive, I6K 
of RAM and an ASCII keyboard with a numeric keypad. 
In actuality, the HS9 is really an HI9 Smart Video Ter- 
minal into which the computer, floppy disk, and interface 
boards have been assembled. 

Two Z-80 microprocessors used. 

There are two Z-80 microprocessors used in it, one for the 
computer and one for the smart terminal; each unit can thus 
operate independently to allow the H89 to process data at a 
high speed. 

The basic unit comes with a 2-MHz Z-80 microprocessor 
and I6K of RAM, but is expandable to 48K. Expansion 
is very easy, because the Heath designers apparently tore 
a page out of the Apple's designer's book and provided 
empty sockets already in place in the computer. Thus all 
that is needed to expand the memory is to buy extra chips 
and plug them in. It should not take more than 15 minutes. 

With 48K of memory space dedicated to user RAM, and 
since the Z-80 can address 64K of memory, another 16K 



of memory must be accounted for, and it is. Two 8K. sec- 
tions of memory are reserved for system use. The first 8K 
section is located in low memory. Of that, 3K is used for 
system ROM and IK for system RAM. The remainder is 
not currently used. The other 8K block of memory that is 
reserved is in high memory and it is currently not being 
used. 

The display is presented on a bright 12-inch CRT that 
contains a P4 phosphor. The screen format is 25 lines by 
80 characters, for a total of 2000 characters. One disadvan- 
tage of the display is that it is not a memory-mapped dis- 
play and thus it is not possible to access individual loca- 
tions on the screen by POKEing a value into a specific 
memory location. In displaying information on the screen, 
several different dot matrix formats are used. To display 
upper case letters, a 5 x 7 dot matrix is used, while a 5 x 9 
dot matrix is used to display lower case letters with de- 
scenders. And, to display graphics characters, an 8 x 10 dot 
matrix is used. 

The terminal part of the H89 will operate at twelve dif- 
ferent, keyboard selectable, baud rates up to 9600 baud. 
The Z-80 that is included in the terminal adds some ver- 
satility to the terminal so that some desirable features are 
available. Among those are the ability to insert and /or 
delete characters or full lines of information. It also makes 
possible a graphics capability. Another handy feature is 
reverse video. That allows the user to emphasize any par- 
ticular section of the screen by printing black letters on a 
white background. 

As any true terminal must have, the H89 has a full ASCII 
keyboard. The 84-key heavy-duty keyboard consists of a 72- 
key standard typewriter keyboard and a 12-key numeric 
and control-function keypad. In addition to providing access 
to the full 128 ASCII characters, the keyboard also pro- 
vides access to 33 predefined graphics characters and it 
has eight keys that are reserved for user-defined functions. 
To simplify and speed the entry of numerical data, a 12- 
key pad is provided. And if the shift key is used with sev- 
eral of the keys on the pad, control of the cursor for inser- 
tions and deletions is provided. 

Borrowing another design idea from the Apple 11 corn- 



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HEATH H19 INTELLIGENT TERMINAL Is basis 
for the H89, Note provision for disks, at right 



puter. the H89 contains a small loudspeaker which is used 
to generate an audio "beep" that is used whenever the 
BELL character (ASCII character 7) is printed. That is 
important, because in good interactive programs, the bell 
can be used to warn the user of an impending change of 
state or overflow condition. Also, the speaker can be used 
to generate various tones and crude music under software 
control. 

Hard-sector floppies used 

A WANGCO/Siemens model 82 minifloppy-disk drive 
is used in the H89. That particular drive requires the use 
of hard-sector diskettes that have 40 tracks-per-diskette, 
I sector- per-t rack and 256 bytes-per-sector. That provides 
slightly more than 100K of data storage per diskette. The 
data transfer rate to and from the disk drive is at 128 kHz. 

For applications where 100K of on-line data storage is 
not enough, an optional H77 Floppy-Disk System can be 
added, for only $595. That adds another 100K of storage to 
the system. And for still more storage, an HI7-I ($345) 
floppy-disk drive, can be added to the H77. That will give 
you 300K of on-line storage. 

For the economy-minded, who feel they can get along 
without a disk drive (and those people are few and far 
between). Heath offers the H88-5 audio-cassette interface. 
That system operates at 120 bytes-per-second and uses a 
2.4-kHz signal for its mark tone and a 1.2-kHz signal for 
its space tone. 

System documentation included 

Unlike some personal computers, the H89 comes with 
a 260-page Operation/Service Manual to teach the basics 
of microcomputers using the H89 as an example. The book 
includes detailed circuit explanations, digital timing se- 
quences and trouble-shooting tips. In addition, a Software 
Reference Manual, 440 pages long, discusses five systems- 
software packages that are available. Another 110-page 
book provides all of the information required for the op- 
tionally available Microsoft BASIC. 

The five major systems -software packages available 
for the H89 consist of the Monitor, HDOS, Dbug, Edit, 
ASM, and Benton Harbor BASIC. The Monitor is sup- 
plied as 2K of ROM firmware and is activated when the 
system is turned on. It allows the user to display and change 
data in RAM, load and run programs from cassette tapes, 
and boot the disk if one is present. Heath's Disk Oper- 
ations System (HDOS) keeps track of data written to and 
read from the disk drives. Benton Harbor BASIC is a lan- 



A NUMBER of peripherals, such as the H14 printer, are available from Heath. 



guage that was originally written for the H8 computer, but 
was carried over to the H89 as well, to provide upward 
compatibility. That, by the way, is something that Heath is 
very conscious of. In fact, when talking with outside soft- 
ware manufacturers. Heath has required that when ma- 
chine-language programs are written for their computers, 
all programs must be in 8080 code so that they will be 
compatible with all Heath computers, the older H8's and 
the newer H89's. 

Microsoft BASIC now available 

Recognizing that Microsoft BASIC was fast becoming 
a de facto industry standard, and that it also was quite a 
good BASIC, Heath has also arranged for it to be avail- 
able on the H89. The H89 Microsoft BASIC contains 116 
commands and functions, compared to the 73 in Benton 
Harbor BASIC. It also features a built-in program editor 
so that individual lines can be edited without retyping the 
entire line. 

For those hardy souls who prefer to program in machine 
language. Heath offers a 3-module set of programs to 
edit, assemble, and debug programs. Again, clinging to 
their desire to maintain compatibility with the old and the 
new. Heath has chosen to provide an assembler that works 
in 8080 code. In the Edit mode, the user can type in text 
to form source files for assembler programs. Once a source 
file has been created, the command ASM is invoked to put 
the assembler into operation. The assembler takes the 
mnemonic version of the assembly-language program (the 
source) and converts it into the hexadecimal digits that 
represent machine language (object code). And if you're not 
perfect, then after you try to assemble your program, you'll 
have plenty of use for the Dbug program. 

The Dbug program allows the user to single-step through 
a machine- language program and to inspect the contents of 
memory locations and data registers, making alterations 
wherever he wants to. Another convenience of the Dbug pro- 
gram is that it makes it easy to load and dump assembled 
programs onto diskette. 

Here are the prices 

The H89 is available, in kit form, with 16K of RAM and 
an audio-cassette interface for $1695. A fully assembled 
H89 (known as the WH89) with 48K of RAM and a serial 
interface, with a built-in minifloppy disk drive, but with- 
out the audio cassette interface, is $2895. The H89 can be 
purchased without the built-in disk drive, but with an audio 
cassette interface, as the H88 for $1295. R-E 




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It isn't that great a leap from calculators 

to computers. Texas Instruments, having 

captured one market, now enters the other 

with the Model 99/4 personal computer. 



TEXAS INSTRUMENTS (TI), INITIALLY A MAJOR MANUFACTURER 

of semiconductors, became a leading supplier of consumer 
products when they launched their digital watches and cal- 
culators on the world market. TFs first entry into the field 
was not overly impressive, but they have moved from that 
low point to become the major U.S. manufacturer in the 
calculator market. Throughout 1979, rumors abounded 
thai TI was going to announce an entry into the home- 
computer market and existing manufacturers feared that 
the Texas giant would come out with a product that would 
quickly dominate that market also. At the Consumer Elec- 
tronics Show in Chicago, June 1979, the suspense ended. 
TI showed their home computer — the TI Mode! 99J4 — and 
the industry heaved a sign of relief. Its St 150 price (since 
raised to $ 1400) non-standard keyboard, and limited capabili- 
ties meant that TI's entry would pose little threat to other 
computers already on the market. 

By and large, that first industry reaction has proven to 
be accurate. A year after its introduction, the TI 9914 is 
Still not well accepted in the marketplace. But don't count 
TI out yet. After a slow start in the calculator market they 
surged ahead to dominate it and they may do the same with 
computers. 

The basic TI 9914 consists of a 40-key keyboard, 16K of 
random access memory (RAM), 26 K of internal read-only 
memory (ROM), and a separate 13-inch color monitor dis- 
play. The heart of the computer is a TI 16-bit micropro- 
cessor chip, the TMS 9900 — and the 99 S 4 is the only home 
computer on the market that has a 16-bit processor in it. 
While that could give it a tremendous advantage over all 
the other 8-bit computers (it means that more memory is 
directly addressable by the microprocessor, and machine 
language instructions in 16-bit micros are generally more 
efficient than those in 8-bit units), Texas Instruments has 
decided to keep the user from accessing the full value of 
that capability. Much of it just amounts to potential advan- 
tages hidden in the machine. 

The system provides some nice features, such as color 
graphics, music, and programmable sound effects. The 
graphics, which can have a resolution as high as 192 x 
256 pixels in 16 colors, can be really great, especially 
since the computer comes with a high-resolution Zenith 



color monitor. But here again, TI thought only about their 
own interests and not those of the consumer. The high- 
resolution color graphics are only available from pro- 
grammed ROM cartridges, and the ROM cartridges are 
only available from TI. Even if you buy the cartridges from 
another company — such as Milton Bradley, which has 
produced some games for the 9914 — the cartridges are still 
manufactured by TI. After all, their major business is semi- 
conductors. If the user wants to write programs that use 
graphics, he is stuck with low-resolution graphics that don't 
come close to the real capabilities of the computer. That 
is because TI chose not to allow the user to access memory 
directly. For example, the high-level computer language 
known as BASIC normally provides PEEK and POKE 
commands that permit the user to access specific memory 
locations. TI's BASIC has no PEEK or POKE commands. 

Keyboard is too small 

The keyboard layout on the TI 9914 is in the standard 
staggered key format, but the keys are smaller than the 
standard typewriter keyboard and extra care is required if 
it is to be used by someone who knows how to touch-type. 




PLUG-IN COMMAND MODULES contain programs In ROM. 




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ACOUSTIC COUPLER allows the 99/4 to talk to other computer*. 



In addition, the keys are calculator-type switches, not the 
standard keyboard-type switches, and if you place your 
hands on the keyboard in the standard touch-typing con- 
figuration, you realize that there are keys missing on the 
right-hand side of the keyboard. Commodore was the first 
company to make the mistake of using a nonstandard key- 
board when they introduced the PET computer and they 
got a lot of flak for it — so much that in the next model they 
came out with a standard keyboard. It's a pity that TI 
didn't learn from Commodore's mistake. 

The 9914 has the ability to address up to 72K of memory 
in its present configuration. That consists of I6K of RAM 
(random access memory). 26K of internal ROM (read only 
memory) and up to 30K of ROM in the form of solid-state 
command modules. The internal ROM contains 13-digit 
floating-point TI BASIC, which is billed as being fully com- 
patible with ANSI Minimal BASIC. That can be misleading 
however; just about every BASIC available today is com- 
patible with the ANSI standard, because it is so narrow in 
its scope. Even with that compatibility with the standard, 
many are incompatible with each other. Since TI BASIC 
is not compatible with Microsoft BASIC, the de facto in- 
dustry standard, novice users may find the book, "Intro- 
duction to TI BASIC", by Inman, Zamora, and Albrecht, 
useful. (The authors wrote the manual supplied by TI with 
the computer.) It is published by Hayden Book Co. Inc. 
and sells for S9.95. 

In addition to its 13-digit accuracy, TI BASIC includes 
commands to handle color graphics, and sound and music 
generation over a full five-octave range. Altogether, TI 
BASIC contains 24 BASIC statements and 14 commands. 
Sounds and music are generated by a built-in program- 
mable music synthesizer that features three voices and 
white noise. The frequency range covered is 1 10 Hz to 
40 kHz (five octaves) and the duration of each note is vari- 
able and programmable from 1 ms to 4275 ms. The volume 
is adjustable up to 30 dB. Another capability of the com- 



puter, also in the area of sound, is speech synthesis. That 
is not available in the basia unit, but in an accessory device. 
The solid-state speech synthesizer costs $149.95, which 
is fairly inexpensive compared to other speech synthe- 
sizers. It comes with a 200- word vocabulary and allows the 
user, under program control, to have the computer give 
verbal prompts. Also, the quality of speech is quite good. 
Additional vocabulary modules with different words will 
be made available. 

Included in the available accessories is a 360-degree, 
multiposition joystick with a side-mounted "fire" button. 
The joystick is connected via a 4-foot cable and two of them 
can be connected for real time competitive games. 

Software 

Software for the TI 9914 is available in two forms: cas- 
sette tapes and solid-state Command Modules. The Com- 
mand Modules plug into a slot in the keyboard console 
and each one can contain up to 30K of programming. TI 
has several modules available on different subjects. In the 
area of educational aids there are grammar, math, and 
early reading. Business-related programs are also avail- 
able such as investment analysis, statistics, personal record 
keeping, and tax aids. Games that are available in modules 
from TI are video chess and football . 

In an interesting marketing marriage. TI and games man- 
ufacturer Milton Bradley have arranged for a number of 
Bradley's games to be available in software modules. Spe- 
cifically, Yahtzee (a dice game). Hangman (a word game). 
Zero Zap (a pinball game) and Connect Four (a strategy 
game) have been made available. Command modules both 
from TI and Milton Bradley range in price from $19.95 
for video graphics to $69.95 for video chess. 

Peripherals 

The TI 9914 keyboard console includes a number of con- 
nectors for adding peripherals to the system. In addition to 
the speech synthesizer, peripherals available from TI in- 
clude a 5.25-inch mini-disk drive ($499.95), a disk drive con- 
troller ($299.95), a thermal printer ($399.95), a telephone 
modem ($224.95) and an RS-232 serial interface ($224.95). 
Also available is an RF modulator for $75. That is grossly 
overpriced and potential 9914 owners would do better buy- 
ing modulators from an outside source at 1/4 to 1/2 the price. 

One measure of how successful a personal computer is 
on the market is the number of independent vendors that 
support the computer. It is interesting to note that even 
after a year on the market, to this author's knowledge, 
there is not a single hardware manufacturer supporting 
the 99/4 and less than a handful of software vendors pro- 
ducing programs for it. In fact, chances are that if you walk 
into half a dozen computer stores in your area, you'll be 
hard pressed to find one that carries any software for the 
9914, aside from that supplied by TI. R-E 







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You'd be surprised at who's getting into the computer field 

(or maybe you wouidn't). Here's information on some products that 

have been around awhile — and on some interesting newcomers. 



WITH PROSPECTS OF PERSONAL COMPUTER SALES EXCEEDING 

500,000 units by the end of this year, more and more com- 
panies are entering the market. Since the Altair 8800 was 
made available in kit form from MITS, Inc., five years ago, 
personal computer interest has soared. In 1976, the Apple 
was introduced by the Apple Computer Co, , Inc. and was 
shortly followed to the market place by Commodore's 
(Personal Electronic Transactor) PET and Radio Shack's 
TRS-80. 

Those three companies represent the major influences 
on personal computer sales in 1980, But other computer 
manufacturers, such as Ohio Scientific and Cromemco 
Inc., intend to increase their share of the market with new 
and exciting products. 

More significantly, several of the world's largest manu- 
facturers of toys and electronic games — Exidy, Mattel, 
Atari and APF Electronics — see the personal computer 
market as a natural extension of their home entertainment 
and education markets. Thus each of those firms has 
dedicated considerable funds to develop computers that 
would serve that market adequately. Some, such as Exidy 
and Atari, have developed a basic computer that will work 
well strictly in programming applications or for use as a 
video game. Others, such as APF and Mattel, have devel- 
oped a sophisticated video game component, to which a 
keyboard can be added later to produce the final computer. 

With the latter approach, the marketing strategy seems 
to be to capture the interest of the consumer first with a 
high-level "toy" that can be a powerful learning tool as 
well as a talented opponent in home games. After the initial 
investment in the game component, the owner — or more 
likely the owner's parents — can later add the keyboard 
component and thus have a relatively powerful computer 
with a wide variety of educational, business, and financial 
software available. 



Compucolor II 

Compucolor, a division of Intelligent Systems Corp., 
made a bold decision when it introduced its Compucolor II 
personal computer in 1978. Rather than entering the market 
with a computer without a cassette (as some others had 
done), or a mini-disk drive (as most others had done), or a 
color monitor (as all others had done), Compucolor offered a 
self-contained, two-piece, deck-top unit that included a 
keyboard chassis connected via ribbon cable to a high- 
quality color monitor. The unit also contained a built-in 
5 IK minifloppy disk drive. Not only was the system unique 
in that the owner went directly to a diskette, rather than 




COMPUCOLOR II can combine business with excellent color graphics. 



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ading from a cassette, but the owner was saved from 
the frustrations of arguing about who could use the family 
color television set during prime viewing time. 

Several models available 

The Compucolor II computers all have the same central 
processor, an 8-bit 8080A. The model 3 comes with 8K of 
RAM, the 5 IK minifloppy disk drive, and a high-resolution 
color-video monitor. All of that costs $1595. The model 4. 
comes with 16K of RAM and sells for $1795, while the 
model 5, has 32K of RAM and sells for $2095. Finally, a 
special 16K. Compucolor computer with an oversize 25" 
screen is available for schools for $2895. 

An extended version of Microsoft BASIC is used in the 
Compucolor computers. Special commands have been 
added to it to accommodate the color-graphics capabil- 
ities of the machine. Two other language capabilities are 
available as well. For 575, FORTRAN IV can be purchased 
for the machine: and for only $24.95, an assembler. 

Disks have a few disadvantages 

Until recently, owning a Compucolor computer had one 
big drawback: You had to buy blank diskettes from Compu- 
color, because a special formatting is used on the diskettes 
and Compucolor wouldn't tell anyone else how to do it. 
They were the only source for those diskettes, which, 
consequently, cost more than they should have. The result 
was that Compucolor owners balked at their involuntary 
continued connection with Compucolor, but Compucolor 
had a perpetual market for its blank disks. Worse than that, 
commercial software manufacturers refused to support 
that machine, because they, too, were required to pur- 
chase formatted diskettes from Compucolor. (Compu- 
color's price was higher than what commercial software 
houses could buy diskettes for elsewhere, so prices for 
software would have to go up considerably.) To my knowl- 
edge, even today, Compucolor is the only source for pro- 
grams to run on the Compucolor computer. 

Recently, the disk situation has changed and a formatter 
program that will format blank diskettes properly for use on 
the Compucolor computer is now available. Another problem 
with the Compulcolor disk system is that a formatted diskette 
will only hold 51 K of program or data. That is the lowest 
amount of data being stored on 5 '/4-inch minifloppy 
diskettes that I know of. The company claims that the 
diskettes they supply can be used on both sides. But that's 



no better than having two separate diskettes, because on- 
line storage is limited to 51 K per drive. The reason is that 
while programs can be stored on both sides of a diskette, 
the drive used can only access one side of the disk at a 
time. By the way. if additional disk storage is desired, an 
extra drive can be purchased for $395. Compucolor is work- 
ing on two advances in disk storage, an 8-inch drive and a 
25 megabyte hard disk. 

There are three different keyboards offered for use with 
the Compucolor computer. The least expensive one, which 
is standard with the basic unit, is a 72-key ASCII keyboard. 
For an additional $135, the expanded keyboard can be sub- 
stituted for the standard one. That unit features numeric 
and color-coded keys that can be used to specify color 
graphics when desired. For the person who wants to go 
first-class all the way. a deluxe keyboard can be substituted 
for the standard one for only S200 more than the base price. 
That deluxe keyboard also offers a numeric key pad and has 
16 additional function keys. 

While input for the computer normally comes from the 
keyboard, output from it normally goes to the 13-inch 
color- video display. The screen can display characters 
in two modes. In its most dense mode it is possible to get 
2048 characters on the screen in a 64-character per line, 
32-line per screen format. If larger characters are desired, 
it is possible to double the size and get 36 lines of text on 
the screen. 

In addition to its text-display modes, the Compucolor 
computer has a 128 x 128 point graphics-display mode 
in which it is possible to display 8 foreground and 8 back- 
ground colors. A nice feature of the graphics mode is that 
it is possible to mix graphics with text, with characters 
capable of blinking, if desired. 

Exidy Sorcerer 

Exidy, a major manufacturer of coin-operated video 
games, entered the personal computer market in 1978 with 
the Sorcerer computer. The 13-pound keyboard console, 
which does not include a video display or a cassette tape 
recorder, contains a 63-key ASCII keyboard that allows 
you to access the full 128-character ASCII set, as well as 
128 programmable graphics characters. The keyboard 
also contains a 16-key numeric key pad. 

On the right side of the keyboard console, is a removable 
plug-in cartridge that physically resembles a standard 
8-track stereo cartridge. Many people believe that it is; 
however the cartridge is really a ROM PAC that contains 
8K of read-only memory. When the Sorcerer first came 
out, it was equipped with a BASIC ROM PAC that con- 
tained Microsoft 8K BASIC. Nowadays, that costs extra. 

The original Sorcerer was available in 8K, I6K and 32K 
versions. However, because of many problems with the 
original circuit board, it was redesigned and at that point 
provision was made to add an extra 16K of memory, so that 
later units now are capable of being expanded up to 48 K. 

It had great potential but... 

When the Sorcerer first came out, it looked as if it were go- 
ing to give the PET, the TRS-80, and even the Apple a run for 
their money. It promised a lot and seemed to take the good 
points from all of those machines and combine them into 
one. It had the standard PET graphics character set, but 
allowed the user to define his own graphics characters and 
assign them to any key. It had a "real" keyboard, which 
the PET didn't. It had a Z-80 microprocessor like the 
TRS-80— and like the TRS-80. had the longer 64-character 
line. Like the Apple, it had a very fast cassette-tape inter- 
face — 1200 baud as opposed to the 300- and 500-baud in- 
terfaces of the PET and the TRS-80— but it also permitted 
programs to be read and stored at 300 baud if desired. And 
it featured higher-resolution graphics than the Apple (240- 
x-512 dots), making it possible to get unbelieveably 
beautiful graphics. 



Graphics 

The Sorcerer has some other nice features, too. It has an 
expansion box that is compatible with the S-100 bus, making 
a raft of accessories, both hardware and software, avail- 
able for use with it. It also has a Centronics compatible 
parallel printer interface built in. as well as an RS-232 
serial interface and a dual-cassette interface. 

With all that going for it, how could the Sorcerer help 
but be a big hit? It's simple. The human interface, both to 
the machine and the company, was terrible. One of the 
biggest drawbacks of the Sorcerer is that it has no screen 
editor. For the uninitiated, that means that if you make a 
mistake when entering a program and you notice it after 
the Sine has been entered into memory (in other words 
after you press the return key), it is not possible to list 
the line on the screen and then move your cursor to it and 
correct it. Instead, you must retype the entire line in again. 
While that may seem insignificant, its importance is quickly 
realized after a few long programs have been written. 
Exidy's answer to that was that if you bought the word- 
processor cartridge, which sells for $199. you can over- 
come the problem. That's a lot to pay for a feature that 
should be standard (and is on most other machines). 

Another problem with the BASIC is that it is not possible 
to list a particular line or a range of lines. You can only 
list a program from the beginning, or from a particular line 
number, to the end of the program. And if you wish to stop 
the listing, you have to type a control-c. There are 
many other problems with the Sorcerer. It is altogether 
too easy to wipe out the program you are working on by 
exiting to the monitor and coming back to BASIC. While 
a warm-start return to BASIC is provided, this is still a situ- 
ation that arises all too often. 

What is one of the biggest problems with the Sorcerer 
is its absolutely atrocious documentation. It comes with 
two manuals but even after reading both of them you still 
don't know what all the capabilities of the machine are or 
how to implement them. An additional manual, originally 
produced by a Sorcerer user, is now being made available 
by Exidy. That clears up a large number of the questions 
left unanswered by the other manuals, but not all of them. 

If you have a problem and try to call Exidy for a solu- 
tion, don't be too hopeful. While there is someone who 
fields such phone calls, that person is not always available 
and, when available, is frequently less knowledgeable than 
the caller. In my particular case, several phone calls that got 
me connected to several different people, resulted in the ex- 
pected — several different answers. The particular question is 
not important, but the response is. One response was: "I 
don't understand what you're talking about." Another was: 
"It can't be done." Still another was: "I think someone here 
wrote a program that can do that but I don't remember who." 
The question was never answered satisfactorily. 

But all is not lost for the Sorcerer, Exidy's latest plans call 
for getting away from the hobbyist and aiming the Sorcerer at 
business applications. Let's hope that the quality of Exidy's 
service department grows along with its aspirations. 

The Sorcerer with 16K of RAM sells for $1295; with 48K 
of RAM, the price is $1495. A 12-inch black-and-white 
monitor is available for the outrageous price of $499. For 
users requiring fast mass storage, a floppy-disk subsystem, 
using 5V4-inch minifloppy-disk drives that can store 120 
kilobytes of data on a diskette, is available for $1 150. That 
includes the controller. Additional drives cost $795, A 
combination video-monitor/disk-drive subsystem, which 
will store 308 kilobytes per drive and comes with two drives, 
is available for $2995. 

APF Imagination Machine 

APF Electronics' Imagination Machine, also known as 
the JM-l, is a home-entertainment center for fun and games 
and also an effective personal computer for serious activ- 
ities such as education. The IM-l features music output, 



in color, and a built-in dual-track cassette recorder 
that permits voice to be played back on one track, and 
machine-readable data on the other. 

The IM-l consists of two components, a computer con- 
sole ($500) and an MP 1000 game controller ($130). The 
console includes a 53-key typewriter-style keyboard, 8K of 
RAM. a built-in dual-track cassette recorder, an audio 
section with a sound synthesizer, microphone input, vol- 
ume control, and loudspeaker. A helpful feature on the 
keyboard console is the printed instructions for single-key 
entry of the 24 BASIC commands available. 

The MP 1000 game console, which contains its own I IK 
of RAM, has been marketed for quite a while by itself as a 
stand-alone TV game. It contains two 4-directional joy- 



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IMAGINATION MACHINE, from APF, makes a good Introductory computer. 

sticks with numerical keypads and "fire" buttons. The 
MP 1000 fits into a cutout in the keyboard console and is 
connected to it by means of a sturdy "U" connector. 

The two-component combination, or IM-l, offers 9K 
of RAM and 10K of ROM and has a video-screen format 
of 32 characters per line, by 16 lines. Output is sent to an 
ordinary black-and-white or color television set via a built- 
in RF modulator. 

Software for the APF computer is available in two forms. 
ROM and cassette tape. Among the programs available 
on cassette are Typing Tutor, Math Tutor, Budget Man- 
ager, and Artist & Easel. The solid-state ROM cartridges 
provide such games as Blackjack and Backgammon as 
well as APF's I2K BASIC, which is not a Microsoft BASIC. 

Musical entertainment is possible by applying a series of 
symbols after the MUSIC command is entered; tunes with 
a musical range of up to three octaves can be played with 
the built-in synthesizer and speaker. Another form of art 
available on the IM-l is computer-generated graphics. In 
the "low" resolution mode, up to 16 shapes — in up to 8 



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colors — can be displayed in 512 cells of 32 columns by 12 
rows. In the "high" resolution mode, up to 128 x 192-dot 
resolution is possible. 

Accessories recently introduced for the IM-I include 
a printer, modem, minifloppy-disk drive system and a 
memory-expansion unit. That last one is the most serious 
shortcoming of the IM-l. Currently, it is only expandable to 
a maximum of 16K of RAM. While that should be sufficient 
for most applications: it is desirable to be able to go farther. 

Cromemco Z-2 computer 

Cromemco Z-2 computers, for the most part, are directed 
towards the most serious business, engineering, and scien- 
tific professionals. At the high end of its product span, the 
Z-2 system includes 1 1 megabyte hard-disk drives, a multi- 
user system capable of handling up to eight users and 
memory expansion up to 5I2K. But at the low end of their 
line, they do indeed supply small systems that fall within 
the budget of the personal-computer/small-business owner. 

First, Cromemco computers are not packaged in flashy, 
color-molded cases. Instead, they are housed in standard 
19-inch-wide cabinets, suitable for rack mounting. The basic 
Z-2 unit contains slots for 21 memory and I/O boards plus 
room for two minifloppy-disk drives. With 4K of RAM. 
and no disk drives, the basic Z-2 costs $1290. When a mini- 
disk drive is added, the system becomes a Z-2D. A Z-2D, 
with 64K of RAM sells for $3785 and with two drives it 
costs $3990. 

Basic input and output to a Z-2 computer must be done 
through a terminal, preferably a CRT leminal, Cromemco 
offers one. the 3102 CRT Terminal, for $1995. It features 
a 1 16-key ASCII keyboard with 20 user-definable keys and 
a 14-key numeric pad. It also has a 12-inch CRT display 
that will show 1920 characters on 24 lines of 80 characters 
each, using a 7 x 9 dot matrix display. 

Since the Z-2 is designed to support the S-100 bus, there 
are a host of other peripherals available for it. Software 
that is available includes several versions of BASIC. FOR- 
TRAN, COBOL, CP/M, and a Z-80 Relocatable Macro 
Assembler, to name a few packages. 

Atari 400 and 800 

Atari, well known for its sophisticated home and arcade 
games, offers two personal computers, the Atari 400 and 
the Atari 800. The Atari 400 is in the $600-price class and 
includes a touch-sensitive, 57-key, flat keyboard (here's 
another company that didn't learn from Commodore's 
mistake) with upper and lower case letters, graphic sym- 



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ATARI 400 is one of two computers offered by this manufacturer, 

bols, and full screen-editing functions. 

The basic machine comes with 8K of memory that 
translates into only 5K for the user, because the computer 
uses the other 3K for internal operations. That 5K however 
winds up being more like the equivalent of 3K because 
of the inefficient way in which BASIC programs are stored 
in memory. That is another BASIC that was not written by 
Microsoft, but by Shepardson Microsystems; it is also 
a BASIC that is going to give its owners a lot of problems. 
Aside from its wasteful use of memory, it handles strings 
entirely differently from the way Microsoft BASIC handles 
strings. As a result, 90% of the programs that appear in the 
hobby-computer magazines will not be usable as they are, 
and will probably require significant alteration to get them 
to run on an Atari computer. 

A single-cartridge slot is available for plug-in software. 
That is normally occupied by the BASIC ROM cartridge. 
While the 400 comes with only 8K of RAM, it is possible 
to send it back for upgrading to I6K of RAM. That is the 
maximum amount of RAM possible in the 400. Because of 
its memory limitations and nonstandard keyboard, the 400 
will probably die a fairly rapid death as those people who 
absolutely must have an Atari computer opt for the 800. 

The Atari 800 is priced from $1000 and boasts a full- 
size tvpewriter-type keyboard. It comes equipped with 
8K. of RAM, 8Kof internal ROM and 8K of BASIC in a ROM 
cartridge. Unlike the 400, however, the 800 has room to 
place memory-expansion modules that can contain 8K 
or 16K of additional RAM. Be careful how you insert them, 
however. While the instructions in the manual tell you how 
to put them in by referencing the printed material on the 
top of the memory cartridge, some cartridges have been pro- 
duced with that information upside down. Thus, trying 
to insert the cartridge according to instructions could pos- 
sibly result in damage. Internal ROM can be expanded to 
26K. 

As far as mass storage is concerned, up to four mini- 
floppy-disk drives can be added to the computer, Each 
drive is capable of storing 92 kilobytes of data on a diskette, 
resulting in a maximum on-line capacity of 368K, 

Among the recent peripherals announced for the 400 
and 800 are the Atari model 825 80-column. dot matrix. 







WIDE RANGE of accessories Is available for the Atari BOO. 

impact printer: the Atari model 830 Modem and the Atari 
model 850 Standard Interface. That interface permits con- 
nection of RS-232 and other peripheral devices to the Atari 
computer. 

To tackle the potential problem of nationwide service, 
Atari has entered into an agreement with Control Data 
Corp. to provide service to 400 and 800 owners through 
200 service centers across the country. In addition. Atari 
will market Control Data's powerful Cyberware business 
investment programs which will run on the 800 only. 

Mattel's Intellivision 

Mattel Electronics has invested more than three years 
of design effort into Intellivision, an integrated personal 
computer that is connected to the user's TV set through a 
built-in RF modulator. 

Mattel's approach to the home computer market is sim- 
ilar to APF's, where there are two components, a video 
game, and a keyboard unit. The game part of the system is 
available and is known as the Master Component. It comes 
with two hand controllers, or keypads, with 12 keys each 
and four action buttons. The second part of the system, 
the Keyboard Component, will have a 60-key tactile key- 
board, which will display 40 characters per line and 24 lines 
per screen. Characters will be upper and lower case. Also 
included are a built-in cassette recorder and an 8-bit 6502 
microprocessor. 

The keyboard unit has given Mattel a lot of headaches 
and its introduction has been delayed several times. Lab 
prototypes, which surface at shows, contain Microsoft 
BASIC, but final units are expected to contain Mattel's 
own BASIC. Let's hope it is compatible with Microsoft's. 

In the graphics mode, 15 colors can be displayed in a 
30,720-point array (160 x 192). In addition, 8 moving fore- 
ground symbols are available. To add excitement to TV 



INTELLIVISION from Mattel will do more than Just play games. 



games, a synthesizer chip is included in the Master Com- 
ponent to generate cheers when a goal or a win is scored. 
In the Keyboard Component, the audio channel of the 
cassette recorder can furnish music or sound effects. 

Mattel is currently marketing the Master Component 
and expects to have the Keyboard Component out by early 
1981 . At that time, a 40-column printer and modem are also 
scheduled for release. The cost for an I nielli vision system 
will range from $300 for a system with 2K of RAM, to $800 
for a system with 18K of RAM. 

To satisfy those consumers who consider prompt ser- 
vice an important factor in determining which computer to 
buy, Mattel has arranged for hundreds of Genera! Electric 
(GE) service centers across the country to operate as 
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OWNERS OF STEREO COMPONENT SYSTEMS AND OWNERS OF 

personal computers have one restless desire in common: 
the urge for change. Rare indeed is the stereo-component 
buyer who has not "upped" his system with an improved 
turntable, or added a graphic equalizer or Dolby tape 
deck. The same for the serious computer hobbyist. After 
his initiation into the exciting world of computer applica- 
tions, it is natural to reevaluate his needs for a printer to 
provide permanent, or "hard copy" output, a floppy-disk 
system to add considerably more memory storage than his 
cassette can conveniently provide, or a modem to permit 
him to communicate with other computers and access 
* 'information utilities" {see page 74 this issue). Then there are 
speech and music synthesizers to add more excitement 
and fun to the computerized games he plays, AC controllers 
to permit his computer to control lights and appliances in 
his house, and a host of other devices. 

Peripheral devices permit the basic computer to com- 
municate with the outside world. Hundreds of peripherals 
are available from a growing number of manufacturers 
anxious to penetrate the rapidly growing personal com- 
puter market. Most personal computer manufacturers 
themselves offer a wide line of peripherals for their own 
equipment. 

There are a large number of peripherals that might be 
desirable to add on to personal computers, yet they 
are not available from the computer manufacturers, but 
from independent manufacturers. When the computer 
owner decides to purchase such a peripheral, it becomes 
his responsibility to see that the device is plug-in com- 
patible (meaning that it is hardware- and software-com- 
patible) or else face the task of matching the peripheral 
to his computer. Quite often, a particular peripheral can 
be obtained at a lower cost by buying from a peripheral 
manufacturer instead of the computer manufacturer. Also, 
it is not unusual for a computer manufacturer to delay the 
introduction of a peripheral device until it is sure that 
there's a large enough market for it. The reason is that 
frequently computer manufacturers don't make their own 
peripherals, but purchase them from independent suppliers. 
In order to get a good price they must purchase in large 
quantities. Often it is possible to purchase the same device 
easier, and at a cheaper price, from the independent. 

Peripherals can cost more than the personal computer 
they serve. It is thus important for the user to analyze both 
his current and probable future needs carefully before 
making an additional investment. If you buy more than 
you really need, you will never get a bargain. On the other 



hand, if you buy less than you need, you'll probably have 
to upgrade in a short time, losing again. 

CRT terminals 

In the early days of personal computing {only five years 
ago), hobby computers were most often equipped with a 
series of front-panel switches and LED indicators. More 
convenient input and output required the use of an external 
terminal, generally a CRT terminal. Today's computers 
generally have a keyboard and video interface built in, 
generally eliminating the need for an external CRT ter- 
minal. There are however, instances when those external 
terminals are quite desirable. Most often that occurs with 
computers that are limited to 40-column displays and have 
to be used in applications where 80 or more columns are 
required. A particular example of that is the Pascal system 
offered for use with the Apple I! computer, which is de- 
signed for 80-column operation. 

Well over 500 models of terminals are on the market today, 
and most use the interface standard set up by the Electronic 
Industries Association {EI A) known as RS-232, That stan- 
dard defines the voltage levels, control signals, connectors, 
and ptnouts required. Most display terminals use cathode- 
ray tubes {CRT's) as displays, although a few use flat- 
panel plasma displays. 

Terminals come in three levels of sophistication; dumb, 
smart, and intelligent, A dumb terminal is basically a key- 







CRT TERMINAL is a necessity tor many computer systems 



board plus a CRT display. Add some hardware to provide 
a programmable cursor (next letter-position indicator) and 
the user can now do more than just see what is taking piace. 
That is a smart terminal and permits the user to do such 
editing chores as inserting and/or deleting letters or words. 
Finally, an intelligent terminal not only allows editing, but 
is programmable. Tasks such as moving the top lines up and 
off the screen as new lines are entered and later recalling them 
are possible. An intelligent terminal needs memory to 
handle its varied tasks and thus usually has its own RAM 
and ROM. In addition, it usually has local-storage capa- 
bilities on its own cassette or disk systems. 

Get it in writing 

Using a personal computer to play the various games 
that are available is a lot of fun. When you're finished, you 
turn off the computer and that's that. But if you are using 
your computer for serious business tasks, or to complete 
your income tax, you must finish the job and write out your 
results before you turn the computer off— or lose the 
information. 

So a rather necessary peripheral for the serious com- 
puter buff is a printer; and a printer can cost as much as, or 
even more than, the computer itself. With a printer con- 
nected to the computer, the user has the ability to produce 
a variety of printed material such as program listings, mail- 
ing labels, billing, and inventory records to name a few. 

Printers can be classified in several ways. First, there 
are impact printers that operate by transferring a character 
to paper through an inked ribbon, much the way a type- 
writer does. In contrast, there are non-impact printers that 
use such printing technologies as electrostatic and thermal 
techniques. 

Impact printers that produce either complete, typewriter- 
like characters, or segmented characters formed by a matrix 
of dots, are available. Fully-formed characters are printed 
in a single stroke. With matrix printing, a defined series of 
dots form the character just as a TV picture is created by a 
series of scanning spots on a television screen. Printers are 
also referred to as character printers and line printers. A 
character printer creates one character at a time, and prints 
it. A line printer prepares a group of characters along the 
line at the same time and the line appears to be printed at 
once. The line printer is much faster, but also more expen- 
sive. 

Which is preferable? That depends on the application. 
Fully-formed characters printed by devices with a Selectric 
or daisy-wheel type of print head are sharper and clearer 
than characters printed by a matrix print head. They are 
particularly pleasing for letters and word-processing appli- 
cations. Most applications don't require that, so the matrix 
printers, which are cheaper, are sufficient. For applications 
that require multiple copies, impact printers are usually to be 
preferred over non-impact types. 

Another key factor in the choice of a printer is speed. 
The instantaneous printing speed is the rate at which the 
print head can produce characters. It does not include the 
carriage return time, which in some printers is minimized 
by using bidirectional printing techniques. Something else 
to consider is that the rate at which a printer receives data 
may be faster than the rate at which it can print it. In such 
cases, the printer must contain some sort of buffer (extra 
memory to store the data until it is printed). 

One of the earliest, and still frequently used, printers in 
the low-cost computer market was the Teletype cylinder 
printer, shown in Fig. 1 . A complete set of characters is 
arranged in a series of concentric rings on the printing 
mechanism. To move the proper character into position, 
electronic signals direct the motion of the cylinder 
in a circular, as well as an up-and-down direction. Once 
the proper character is in position, a hammer strikes the 
cylinder, causing it to transfer ink from a ribbon to paper. 



PAPER 




VERTICAL I 
MOVEMENT 
I OF MECHANISM 
EMBOSSED IN W X J 

RINGS AROUND f ^J 

CYLINDER 
FIG. 1— CYLINDRICAL TYPING ELEMENT is capable pf printing speeds of 
up to 10 characters-per -second. This became the first low-cost printer for 
the hobbyist market. 

Used Teletype printers are available from $200 to $500, 
while new ones cost about $1200. 

The Teletype, at 10 CPS (Characters Per Second), is very 
slow and only permits upper-case characters. An improve- 
ment in both of those areas was made with the development 
of printers based on the IBM Selectric mechanism, shown 
in Fig. 2. Here, a type sphere is rotated on its axis until 
the proper character is selected and then the sphere strikes 
the ribbon. That mechanism improved printing speed to 
about 14.5 characters per second. The price tag for such 
printers is in the $I000-to-$400Q range. 

Another design for a letter-quality impact printer is the 
daisy-wheel printer shown in Fig. 3. On each spoke, or 
petal, is a single character. When the hub is rotated to the 
correct position, a hammer is energized which causes the 
letter to strike a ribbon. Both the daisy-wheel and Seiectric- 
type print mechanisms have a wide variety of type fonts 
available, with the Selectric balls offering the wider choice. 
Daisy-wheel printers, such as those produced by Qume, 
Diablo, and Howard Industries operate at speeds ranging 
from 30 cps to 55 cps. Prices range from $2700 to $7000. 

The most commonly used printers in personal com- 
puter applications are matrix printers. That is because they 
are usually the cheapest, generally under $1000. But 
high-performance matrix printers can exceed $9000 in 
price. In matrix printers, the print head contains a vertical 
column of small needle hammers that are moved across 
the page while input is fed from information stored in mem- 
ory. Print heads usually have seven to nine needles in a 
vertical row, and a horizontal matrix that is four to seven 



RIBBON 



PAPER 




EMBOSSED 
CHARACTERS 



PRINTER MECHANISM MOVEMENT 



FIG. 2— THE SPHERICAL TYPING ELEMENT, commonly found on Setectric 
typewriters, offers a choice of typefaces and operates at printing speeds of 
up to 15 characters-per- second. 



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PRESSURIZED 
SUPPLY CARTRIDGE 



columns wide, to form a complete image of the character. 
The larger the matrix, the better the 'character definition. 
In fact, some new printers from Sanders Associates, Cen- 
tronics, and Integral Data Systems, make multiple passes 
over the same character with the head position moved 
slightly each time. That produces a character that has more 
dots and can approach the quality of fully-formed character 
printers. Character- based matrix printers can print at speeds 
as high as 330 cps, while line printers can reach speeds of 
500 lines per minute. 

Non impact printers are generally quieter, cheaper, and 
faster than the impact types; but they are often less legible and 
sometimes require a special paper. Also, they do not produce 
multiple copies on a single pass. 

A thermal matrix printer uses a heat-sensitive paper which 
changes color when heated to 200°F. A typical print head 
contains a 5-by-7 array of dot-heating elements. The head 
forms a single character at a time and moves horizontally 
across the specially coated paper. The speed of such printers 
range from 50 to 100 cps; speed is somewhat limited by the 
need for the dot elements to cool down a bit before proceeding 
to create the next character. Prices for such printers range 
from $500 to $1000. 

Elect rosensitive printers are somewhat similar to thermal 



PAPER 



RIBBON 



CHARACTERS 
EMBOSSED 
ON TIP OF ARM 



HAMMER 




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CHARACTER 
X ARMS 

g FIG. 3— DAISY-WHEEL PR INTERS are relatively expensive but offer letter- 
< quality printing at speeds of Up to 55 characters- per- second. Print wheels 
cc can contain up to 96 characters. 



INDEPENDENTLY 
CONTROLLED 
INK EJECTION 
CHAMBERS 




INK SUPPLY LINE 

INK FILTER 



ELECTRICAHNPUT 



FiG.4 — INK-JET PRINTERS are a relatively new technology and use ink jets 
to produce matrix characters on paper. 

printers in that they also use a specially coated paper, as well 
as a matrix print head. Instead of having heating elements in 
the print head, those have small metallic electrodes. A dark 
paper, coated with a light-colored conductive layer, is pulled 
in front of the print head. To form a particular character, a 
series of pulses are applied to specific head electrodes; a 
voltage breakdown, or arcing, takes place and the conductive 
coating is destroyed leaving the dark areas exposed to create 
a character. To form a different character, voltages would be 
applied to different electrodes on the print head to burn away 
different areas of the conductive coating. 

Another non-impact approach to printing is the ink-jet sys- 
tem, Fig. 4. Here a high- velocity stream of ink, in the form of 
microscopic droplets, is squirted at the paper. The droplets 
are given an electrical charge and passed between electrodes 
whose voltages are varied. The ink droplets are thus deflect- 
ed, much like the beam of a CRT, and form characters on 
paper. The printing speed is high and up to 180 lines per 
minute can be printed. 

Here are some typical prices for a variety of printers. A 
thermal printer (40 cps) for the Apple // computer costs $595; 
an electrostatic model (150 lines per minute) costs $695, and 
an impact matrix primer (60 cps) is available for $1545. A 
matrix impact printer (65 cps) for the PET costs $798. Radio 
Shack markets an electrostatic matrix printer (120 1pm) for 
$239 and several impact matrix printers (up to 120 cps) from 
$999 to $1999. 

When looking at those prices a few things should be re- 
membered. Not ail of the printers have the same capability. 
Some print only 40 columns across while others go to 132. 
Some include tractor-feed mechanisms for the paper, while 
others don't. The prices are not quoted for comparative pur- 
poses — not enough information is presented for that — but 
rather to show a range of prices for currently available 
equipment. 

Need more memory. . .add a floppy disk 

It doesn't take a serious computer hobbyist much time to 
feel a craving for more memory than his cassette can handle 
conveniently. The hobbyist also soon becomes impatient with 
the slow access time of a tape as he rewinds to search for a 
particular section. A disk is a randomly accessible memory 
device that is capable of storing and retrieving information 
considerably faster than a tape system. Of the various types 
available, the minifloppy disk is the most popular in the home 
computer market. 

The floppy disk was first introduced to the market by IBM 
and is somewhat similar in appearance to a 45 RPM record; 
it is more flexible (see Fig. 5), has no grooves, and is perma- 
nently sealed in a square plastic jacket. The only exposed area 






is in a slot cut in the jacket which provides a place for a 
magnetic head to make contact with the magnetic media of the 
diskette. Tolerances in floppy-disk drives are very close and 
the magnetic head is in intimate contact with the rotating 
media. In addition, the speed of rotation is quite high (360 
RPM), so that even a small speck of dust, fingerprints, or 
cigarette smoke can cause a read or write error to the disk, 
Therefire. users are instructed to replace diskettes back into 
their protective envelopes immediately after use. 

IBM's original floppy-disk entry was an 8-inch disk, the 
3740, which featured 77 tracks (48 tracks-per-inch), soft sec- 
toring with 26 sectors-per-track, 128 bytes-per-sector, a re- 
cording density of 3200 bits-per-inch and a speed of 360 RPM . 
Since then, minifloppy disks, 5'/4-inches in diameter, have 
appeared in both hard-and soft-sector formats. 

What is soft sectoring? It is a method by which codes are 
used to identify various sectors on the disk (see Fig. 6i. It 
permits a blank diskette to be formatted in any way desired. 
For example, on the Apple //, diskettes were originally 
formatted as 35 tracks with 13 sectors-per-track and 256 
bytes-per sector, A recent improvement now makes it possi- 
ble for Apple disks lo be coded as 35 tracks with 16 sectors- 
per-track, resulting in 24K of additional data storage on the 
same physical medium. When a soft-sector disk is used, it is 
formatted first and information is stored on it that defines each 
track and sector so that when the disk system wants to store 
data, it can read that information and know exactly where it is 
all the time. 

The second approach to disk storage is hard sectoring. 
Here , a series of holes, one for each sector, is punched on the 
periphery of the center-drive hole. A LED-and- photocell 
combination permits light to pass through the holes as they 
rotate, causing pulses to be generated. The electronic cir- 
cuitry in ihe drive counts those pulses so that the drive always 
knows where the head is on the disk. 

While all floppy-disk systems operate in a similar manner, 
storage densities vary from I70K. for PET diskettes to as little 
as 51 K for compucolor diskettes. Storage capacity is only one 
of the parameters to consider in disk systems. It refers to the 
number of tracks, the number of byte s-per-t rack and the num- 
ber of recording surfaces (some drives record on both sides of 
the floppy disk). Others are access time and transfer rate. 
Access time is the time it takes to position the head to the 
proper track, plus the lime it takes for the diskette to rotate 
and reach the appropriate sector, plus the time to read or write 
the data. The transfer rate is determined by the disk-system 
speed of rotation, recording density, and the number of tracks 
that can be accessed in parallel. 

Recent advances have improved the performance of 
disks and disk systems. To increase storage capacity, double- 
density and double-sided systems have been developed. 
Double-sided systems include a read/write head on each side 
of the diskette and thus result in twice the storage capacity. 
Some double-density systems double the number of tracks 
per side, e.g. on minfloppies from 35 to 77; others simply 
pack more information into the same number of tracks. By 
combining both of those technologies, a fourfold increase in 
storage capacity is possible. 

How does it work? 

A disk-drive system is a sophisticated combination of servo- 
mechanisms and control electronics. When a diskette is in- 
serted into the drive, a spindle locates the center hole and a 
motor brings the speed of the diskette up to 360 RPM . Then 
the read/write heads are positioned over the first track, 00, by 
the small index hole tn the diskette. The heads are next 
positioned to whatever location is desired by a seek operation. 
The heads float over the tracks until the proper position is 
found; then a head-loading coil pulls the heads down (loads 
them) to the magnetic surface of the diskette. When the heads 
must be moved to another location, they are lifted off the 
media (unloaded), moved, and then loaded again. 

There are many applications where it is necessary to store a 



WRITE PROTECT 
NOTCH 



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/ 



/ 



\ 



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7 




PLASTIC JACKET 



READ/WRITE 
HEAD OPENING 



FIG. 5— A FLOPPY DISK is almost fully enclosed In a jacket to protect the 
surface from dirt and physical damage. 



THACK76(END) 






INDEX 


HOLE / 


INDEX 

HOLE 




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00 




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(START) 


SECTOR 
HOLES 


SOFT-SECTORED DISK HARD-SECTORED DISK 


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b 



FIG. 6— A SOFT-SECTORED DISK, shown in a, uses one index hole to 
I oc ate t he d ata on the s urf ace of the d i sk . A ha rd- sectored dtsk, s hown i n 6, 
uses many index holes for the same purpose and is more efficient because 
less computer memory is required for the system. 

lot of information on disk. Frequendy that can exceed the 
storage capacity of a single diskette. For such applications, 
there are other types of disk drives that do not have flexible 
media. Those are called hard disks. A new type of mini hard- 
disk that uses a technology originally developed by IBM has 
just recently been announced. Those disks are known as micro- 
Winchester disks and they provide a phenomenal 6 megabytes 
of storage on a 5W-inch hard disk. Prices for the disks are 
expected to be in the SI 500 range. 

Computers can chit-chat. . .with a modem 

Once a user gets used to working by himself at his personal 
computer, it doesn't take long for him to start thinking of 



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communicating with other terminals, computers, or "in- 
formation utilities." At that time, he is ready for a peripheral 
called a modem (for M0dulator-Z)£Modulator) which permits 
digital informtaion to be transmitted over long distances via 
phone lines. 

Basically, a modem provides a means for a digital signal to 
modify an audio signal so that the digital information can be 
sent over the phone lines. On the sending end, the audio signal 
is encoded, or modulated, with the desired information and at 
the receiving end, it is decoded, or demoduated. The modula- 
tion is generally done by a technique known as FSK {Fre- 
quency-Shift keying). 

Connection of computer modems to telephone lines can be 
direct or indirect. Indirect connections are done via an 
acoustic coupler. The acoustic coupler has a cradle that holds 
a telephone receiver, into which the electronic signals to be 
transmitted are acoustically coupled. With an acoustic coupler, 
the user must dial the phone himself and then place the hand- 
set in the coupler. 

With a directly coupled modem, the modem is connected 
directly to the phone line and, with the appropriate hardware 
and software, it is possible for the computer to dial numbers, 
or answer phones, and then transmit the required data and 
hang up. 

The cost of acoustic couplers is generally about half the 
price of hardwired modems because the acoustic devices must 
then be connected to a serial interface, which generally more 
than compensates for the difference in price. One of the most 
popular acoustic modems is the CAT by Novation Inc., 18664 
Oxnard St.. Tarzana. CA 91356, It usually sells for between 
$150 and $199. The most popular direct connect modem for 
the Apple computer is the DC Hayes Associates, Inc. (10 
Perimeter Park Dr., Atlanta. GA 30341) Micromodem II, 
which sells for about $400. 

Computers can talk and play music 

Computers operate from digital signals, a fact known even 
to the novice. Thus it is startling to hear a voice or music 
coming from a computer. Similarly, it is entertaining to watch 
the reaction of an observer when the owner of a home compu- 
ter commands his computer to do things with spoken words; 
yet the observer, using the same words, cannot get any reac- 
tion from the computer. 

The ability to generate voice or music from digital signals is 
called speech or music synthesis. Music is easier to generate 
than speech, since a musical tone contains a fundamental 
frequency and a series of harmonics. Speech, with its various 
sounds and inflections, is generally a complex, non-repetitive 
waveform that is more difficult to synthesize. 

To generate a musical note, an algorithm is developed and 
the computer is instructed on the duration and amplitude of 
the signal. To form chords, a number of different tones are 




MODEMS LIKE THIS allow computers to use the telephone. 



combined. To generate speech, a variety of techniques are 
used. One approach consists of feeding a microphone's output 
to a computer, where an analog-to-digital (A/D) converter 
samples the waveform and converts it to digital signals, which 
are then stored in memory. For adequate reproduction a high 
number of samples is required, demanding considerable mem- 
ory storage. For example, to reproduce four minutes of 
speech properly would require almost 250K of memory — 
enough to fill an 8-inch floppy disk. 

Another approach to speech synthesis makes use of 
phonemes, basic elements of speech, which do not corre- 
spond to words or letters of the alphabet; instead, they are 
sounds that can be combined to form words. That technique is 
much more efficient in the use of computer memory. The 
drawback is the somewhat unnatural sound that is produced. 
Digitized speech output is available on the Apple II computer 
with the Super Talker, which is a speech-output device pro- 
duced by Mountain Hardware, Inc.. 300 Harvey West Blvd., 
Santa Cruz, CA 95060. The price is about $400. 

The new Texas Instruments 99/4 computer has a solid-state 
speech synthesizer module that contains over 200 predefined 
words in its vocabulary. When the operator types SAY "DOG". 
a bark will be heard from the computer's self-contained audio 
circuits. 

In addition to talking, computers are capable of listening to 
and understanding spoken words. A speech-recognition sys- 
tem generally includes a microphone, a preprocessor, and a 
feature extractor. When the operator speaks into a micro- 
phone, the preprocessor analyzes the spoken word while the 
feature extractor investigates any unique or unusual features 
of the voice. The computer then identifies the word and stores 
the information leading to the decision. That all takes place 
during an initializing session called training. Once the system 
has been trained, it will recognize those words on which it was 
trained. Since the speech-recognition system has averaged 
and stored the unique speech pattern of the trainer, it will 
not always respond to the same words spoken by a different 
individual. As such, it is possible to use it to identify individu- 
als by voice only. 

A variety of other devices used, too 

In addition to those major peripherals, computer owners 
often find need to purchase other devices to improve the 
operation of their system. Those can range from filters for the 
power line to accessory devices such as the Daia Ditbher from 
The Peripheral People in Mercer island, WA that makes it 
easier for the TRS-80 to read computer tapes, R-E 



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INTERFACE AGE will keep you up-to-date on small computer innova- 
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In past issues we have covered these and many other topics; 

HOME: Solar Controller: Computers and the Sun 
Computerizing the Home 
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Selecting Your First Computer 
System of the Month (a regular feature) 
BUSINESS: 10 Big ideas for the Small Businessman 

Simple and Efficient Parts Inventory Control 
A Small Computer Payroll Program 
Exclusive reviews of the latest electronic 
workhorses for the office 

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Fly Your Computer: 
A Flight Simulation Program 



EDUCATION: The Microcomputer Goes to School 

2D Simulation: Educational Breakthrough 

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73 



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THE NEWEST AND FASTEST-GROWING UTILITY TODAY IS THE 

" info rm at ion" utility. Many modern philosophers and edu- 
cators claim that information is power. The more you 
know, the better you can plan. The faster you can predict 
will determine your success as a student, businessman and 
professional. 

Top performing corporations have been using large and 
expensive computers for years to increase their lead over 
competitors; they make use of their "information utilities" 
to power their growth. And now, the home computer owner 
can have access to the same type of computing power so 
that he can search legal documents, track down news stories, 
reserve airline or theater tickets, identify stock market 
prices and trends, research term papers, pinpoint govern- 
ment research projects — all without leaving his home. Low- 
cost timesharing is available now from Telecomputing Cor- 
poration of America's (TCA) The Source, CompuServe's 
MicroNet and Lockheed's Dialog. The information utilities 
are here now, at a modest cost, ready for the home com- 
puter owner to "plug-in" and draw upon enormous stores of 
information. 

Software is the key 

Only five years ago, home computers hardly existed, 
except in the basements of serious hobbyists. Estimates for 
1%0 run to $1 billion in retail sales... that's growth! Although 
the cost of the computer hardware has dropped consider- 
ably, much of the credit for the rapid surge is due to the large 
number of programs, also known as software, available from 
a large number of suppliers. 

No longer is the home computer market limited to the 
serious computer buff who can taiior his software to match 
his hardware limits; now, a novice can purchase a low-cost 
home computer, spend a half hour wiin a carefully detailed 
instruction manual, connect all the pieces together, plug in a 
tape or disk drive and proceed to run a program. Within 
hours he can lose all his hangups and fears and write his own 
simple programs. That's fine — what next? 

The new owner of a home computer can store names, ad- 
dresses and phone numbers of friends, do regular mailings to 
customers of his small business, prepare his weekly payroll 
and other business chores. His wife can keep recipes in the 
computer's memory and balance her checkbook. His chil- 
dren can play games with the computer and use it to learn 
spelling, math and many other subjects. 

Lots of fun, lots of record keeping and lots of choices to 
keep the new "toy" busy. But what next? 

What's next is time- sharing, or the capability to connect 
the home computer with huge data banks or "information 
utilities." A home-computer owner can literally plug into a 



vast library, a huge newspaper network or other large stor- 
age banks of facts, data and information. Until now, only 
major corporations or large government agencies could af- 
ford to store and gain access to such data banks. Now, large- 
scale computer-systems houses are making their data banks 
available to the home computer owner during off-peak 
hours. It makes sense — the data is there anyhow, so why not 
offer it at low cost during hours when the demand is low? 
Furthermore, communications between computers offers 
an attractive alternative to the faltering U.S. mail service; 
electronic mail is another service provided by information 
utilities. 

Getting on line 

It's not difficult to avail yourself of these information 
utilities. Assuming that you are already the owner of a home 
computer, what you must add is a device that will convert 
digital output signals from the computer into audio tones 
that can be sent over the phone lines and, in some cases, a 
serial interface (more about that later) to allow you to con- 
nect this device to the computer. 

Actually, you do not even need the complete computer, 
but can get by with just a computer terminal -the separate 
keyboard and video-display unit used to get information into 
and out of most large, and some small, computers. Using 
your own computer, though, does have its advantages. 

Because the computer is programmable, you can instruct 
it to communicate with one of the networks even when you're 
not around. 

To give one example, suppose you want to get the closing 
Dow Jones averages hot-off-the-wire. but will not be able to 
do so yourself when the news is fresh. You can instruct your 
computer to call up the appropriate computer at a specific 
time and ask for that information. When it is received, your 
computer can either store it in its memory, to await your 
return and instructions, or can automatically transfer it to a 
more permanent storage medium, such as a floppy disk, 
where it will be permanently retained, perhaps as part of a 
data base you'll use yourself to compile a monthly average 
of closing prices. 

In another instance, you might program the computer to 
answer the phone when it rang and, if it detected a computer 
at the other end of the line, to respond to the effect that you 
were not there at the moment but that it would be glad to 
take a message for you that the other computer cared to 
leave. You could even, if you were anticipating a message 
from someone over one of the networks, have a message 
waiting for him in your computer's memory, to be trans- 
mitted when he called. 

The device that actually takes the information from the 



computer and sends it over the phone line, or receives the 
incoming information and translates it into a form that the 
computer can use. is known as a. modem (MOdidatorlDEMod- 
ulator. Modems can be divided into two categories. There 
are acoustically -coupled, and ail -electronic modems. 

The acoustically-coupled kind ties the computer into the 
phone line without any direct connection to the telephone 
company's equipment. It is designed to accept a telephone 
handset and to link the computer with the phone equipment 
through a built-in microphone and speaker, using sound, 
rather than electricity as the medium. The other end of the 
acoustic coupler is connected electrically to a serial port— 
sometimes referred to as an RS-232 interface— of the com- 
puter. 

What's a serial port? Most small computers come with a 
parallel port, generally used to connect to a printer. This is 
fine, as long as you have at least eight wires -one for each of 
the eight bits that make up a single ASCII character. Tele- 
phones, however, use only one line. Therefore, the bits must 
be arranged to travel in single file-or serially -rather than 
in parallel. That is the function of a serial port and, if your 
computer is not equipped with one, it can usually be ob- 
tained through the computer's manufacturer. And, if he 
does not have one available, there's sure to be someone else 
who does sell such an interface that will work with your 
setup. 

Acoustic couplers, though, require you to be present to 
answer the phone and to place the handset into the coupler. 
There's a more elegant method. 

The other type of modem is the all-electronic one which is 
permanently connected directly to the phone line. This 
means that it can easily be programmed to work under com- 
puter control -to answer the telephone automatically, to de- 
termine whether there's a computer at the other end of the 
line, etc. It can also, in many instances, dial a number under 
the computer's direction, as would be the case in the Dow 
Jones example given above. 

This type of modem is usually connected to the computer 
more directly than through a serial port, because of the 
complexity of its functions. Telephone company regula- 
tions may also require that a special coupling device be 



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RANDOM POETRY PLAT POETRY 

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SCORE FOUR AGAIHST THE COMPUTER PLAT SC0REFUU8 

RANDOM SHAKESPERIAH SONNETS.......... PLAT $0HN£T 

FILL IN THE KISSIKS LETTERS PLAY 5PELL 

STAR TREK (SUPER VERSION!] 1 1 - PLAY -TRE* 

PLAY THE STOCK BARKET PLAY STOCKS 

RULE ANCI EHT SUHERIA (A DIFTERENT ONE) PLAY SUMER 

TARGET PRACTICE AS NEAPOHS OFFICER ON THE EN TEN PRISE. PLAY IARGTZ 

TIC TAC TOE PLAY IICTACTOE 

A REGULAR CASINO OF GAMES FROM LAS TEGAS PLAY VEGAS 

ROUCET FOR UP TO SEVEN PEOPLE PLAT WHEEL 

PATROL THE CITT STREETS PLAT WATCHMAN 

HUHT THE RUMPUS -'LAT WMPUS 

NOTE: 

FOR INFORMATION OH ANT GAME TYPE 1HF0 (6AMEKANE) 

I.E.. INFO ADYENTURE; TO VIEW A DEMCIKSTRATION OF CERTAIN 
OF THE NTJRE COHPLEI GAMES. TYPE DEMO (GAHEHAHE). 



TO PLAY GAMES from The Source, type "PLAY," followed by the name of 
the game. 



>UPI N G REJEAH 

ENTER STARTIKG 1 ENDI1E DAtE - OR PRESS RETURN FOR TOOAT 



PICK A STARTING STORY NUMER - FROM I (THE EARLIEST) 

TO 13 (THE LATEST). 

13 

READ F0RHM18 In TIME (ftf). READ BACKWARD (RB), 
SCAR FORWARD (SF) OR SCAN BACKWARD (SB)? 



13 07-03 03:00 ped* 

(9 graf lead, nltkuo Ath draf: the trip xxx _ carter attacks reauan tax 
cut) 

PICK A STARTING STORY NUMBER - FROM 1 (THE EARLIEST) 

TO 13 (THE LATEST). 

13 

READ FORWARD EN TIKE (RF), READ BACKWARD (RB). 
SCAN FORHARS (Sf) OR SCAN BACKWARD (SB) 7 



13 07-03 D3:UU ped- 

(9 graf lead, pickup AtN graf: the trip XXX carter attacks reagan la* 

cut) 

urgent 

previous Washington 

Carter attacks Reagan tax proposal 

By HELEN THOMAS 

UPE White Hpuse Reporter 

LOS ANGELES IUPI) President Carter today attacked Ranald Reagan's 
tax cut proposal as Irresponsible, inf lationary and impossible tp carry 
out without cutting federal social services. 

For his first public comment on the Lax-reduction proposal made by 
bis probable Republican opponent for the presidency 1n Norenber, the 
president flew to the former California governor's bone state. 

He told a weetlnq di the National Education Association, which has 
strnnqlr supported Carter's carina ign. that Reauan" s suggested S3o 
blllinb tax cut Is "a classic free lunch _ something for nothing, 

'That kind of hasty offer can only be called by pne word _ 
irresponsible," the president said. 

"It is sheer deception to prtrnlsc the American people that we can 
have this enOTTXHjsly expensive and unfair tax cut _ that we can 
dramatically increase defense spending - and still maintain social 
erobramt, he said. 

Carter did not mention Reaejan bj narwj but press secretary Jody 
Powell made 1L clear the president was directing his renarks at Reagan 
and other GDC tax-cut proponents. 

Powell also told reporters Carter has not -job up his own ni nd 
shout a tax cut, but has agreed to work with House and Senate Deoocrats, 
who want to pass their own _ lesser tax cut to rival the Republican 
prpppsal . 

Carter was met at the airport by California Gov. Edmund Brown Jr.. 
a former rival for the Democratic presidential nomination. Brown praised 
Carter's cooperation with California officials and said there is no 
hostility between the two men. 

Rrowri has not endnrsed Carter, Asked whether he would. Brown 
replied: 'not this morning ... It's not the appropriate forum for 
that." 

The trip, which will be partly paid for by the Carter- Hon 
WE ARE M'l STORY S3 
TYPE h B" "R- "K" "S h OR "G" AND A STORE NUMBER 

Cull a. 



THE NEWS, even before It's "hot off the wire," from UPt, via The Source. 

added between this type of modem and the phone line, to 
prevent any possible interference with normal telephone 
functions. Many modems have such a coupling device built 
in. 

In all cases, special software will be needed-at the very 
least to enable the computer to communicate via its serial 
port. Software for the more sophisticated modems is gen- 
erally available from the modem's manufacturer to work 
with your particular computer. 

The Source 

An inexpensive information retrieval system, The Source, 
can be tied to a personal computer through a modem, as 
just described, and a toll-free telephone line. Whether you 
own an Apple, Pet. TRS-80, Heath, Exidy, Atari or other 
computer, you can gain immediate access to United Press 
International (UPf) newswires, the New York Times Con- 
sumer-Data Base, airlines schedules and reservations, res- 
taurant and wine guides, tax tables, computer games and 
electronic mail — and that's just for openers. 

The Source is not a novelty or game to while away leisure 
time, although games and educational courses are part of the 
network. It is a low-cost computer service that provides the 
hobbyist, student and small-businessman access, through 
time-sharing, to an enormous information network. The 
system is offered by Source Telecomputing Corp., a sub- 
sidiary of Telecomputing Corporation of America, 1616 
Anderson Rd., McLean VA 22102. 

How cheap is this service? Would you believe only $2.75 
per hour during non-prime time (6 PM to 7 AM, Monday 
through Friday; all day Saturday and Sunday) and $15 per 
hour during prime time? An initial SI 00 hookup charge in- 
cludes a user account number, a secret password (which can 
be personalized) and a local toll-free telephone number to 



o 
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CD 

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75 



CD 
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access The Source in areas where there are a lot of members. 
In areas with only a few members, it may be necessary to 
dial long-distance. To illustrate cost in another way, a user 
with a 300-baud modem (which sends out 30 characters per 
second) could get as many as 200,000 characters of data-base 
information for only five dollars. The subscriber can have 
billing charged to any one of several credit cards including 
American Express. VISA, and MasterCard (formerly Master 
Charge). 

Get the news while It's hot 

UPFs network extends to more than 7000 news-service 
customers who print newspapers, magazines and market 
reports based on timely input. Let's see how a college senior 
with a personal computer could benefit from The Source. 
Assume that he has to prepare a term paper on the political 
strain between the U.S. and Iran. 

As a subscriber to The Source, the student would request 
UPI and then be queried by the computer on whether he was 
interested in National (N), Regional (R), State (S) or Federal 
(F) departments; next whether General (G), Business (B), 
Sports (S) or Miscellaneous (M) news categories. After 
National (N) and General (G) selections were made, the 
screen would request a key word or search phrase to identify 
the request to review U.S. — Iran news stories. The Source 
would then indicate the number of stories available within a 
selected time period (week or month) and allow the sub- 
scriber to scan the first paragraph of each story; if the entire 
story is required, just a simple keyboard command would 
display it on the screen. Thus, within minutes, and without 
leaving his room, the student could access UPFs filed stories 
and prepare a factual, timely paper. How timely? A story on 
a major political move in Iran filed in Teheran would reach a 
Source subscriber within two minutes of its initial trans- 
mission. A fast-reaction newspaper would carry the story 
perhaps hours later. Thus, our college senior could submit a 
term paper to his professor during an afternoon class and 
discuss items that might be covered in the next day's news- 
paper! A clever student could earn many an A with such a 
masterful ploy. 

What's happening back home 

A novel form of news coverage offered by The Source 
is called UPI Newshare, to deliver local news items gen- 
erally considered insignificant for the National. Regional, and 
State categories. 

For example, if your hometown lost the Little League 
Championship, the story would hardly be picked up by the 
major UPI network. However, with Newshare, local news- 
papers will be adding their stories to the UPI computer. 



Jsers of The Source would have quick access to local news 
without waiting days for delivery of their old hometown 
newspapers. And think how easy it will be to keep up with 
news of old friends just by tapping a few keys on your home 
computer. 

Neither rain nor sleet., 

Have you reached your threshold of tolerance for exces- 
sive delays in mail delivery? Electronic mail is just one of- 
fering of The Source. Not only can time of delivery be con- 
siderably compressed, but two-way message exchange is 
possible at modest costs. 

Electronic mail can be "delivered" in three ways. The 
simplest method allows one subscriber to send a message at 
30 characters per second to another subscriber's "mail-box", 
where the second subcriber's terminal indicates Mail Call. 
When the second subscriber types mail on his keyboard, the 
message "mailed" to him will appear on the CRT. 

A two-way message exchange is possible between two 
subscribers in the chat mode. Finally, a message can be 
sent from a subscriber to a non -subscriber via Datapost, a 
service competitive with Mailgram- Datapost is a service of 
TDX Systems Inc., and receives the messages at its center 
located at O'Hare Airport in Chicago; the messages are then 
converted to hard copy and sent on express flights for next- 
day delivery in cities around the country. Cost? Only 75- 
cents-a-message additional charge above The Source and 
telephone line fees. 

Micro Net 

MicroNet, a service of CompuServ Inc., permits per- 
sonal computer owners in 175 major cities in the U.S. to ac- 
cess their large DEC Kl-10 and KI-20 central processors in 
Columbus, Ohio. The MicroNet system offers (1) a variety of 
computer programs on a time-sharing basis, (2) the ability to 
expand the potential of the personal computer, (3) a means to 
buy and sell software through the MicroNet Software Ex- 
change, (4) a Feedback feature to contact MicroNet head- 
quarters at no charge, and (5) nationwide contact via its 
National Bulletin Board and Electronic Mail capabilities. 

The personal computer service is only available during off- 
peak hours. 6 PM to 5 AM weekdays and all day Saturday, 
Sunday and holidays. MicroNet may be accessed via local 
telephone service from more than 175 major metropolitan 
areas. The service costs $5 per hour connect-time in over 30 
proprietary cities; an additional $2 per connect-hour sur- 
charge is added for customers using MicroNet from TymNet 
network cities. (TymNet is a telephone-interconnect network 
between MicroNet and several major cities. Thus, if you live 
in one of these major cities and you use TymNet, you will be 
billed for local phone calls when accessing MicroNet.) The 
initial fee is $9; however, the first hour of use is free, thus 
reducing the cost by $5. 

Among the programs in the MicroNet library are (1) BASIC 
with double precision, linking capability, file-to-file sorting 
and a debug mode, (2) FILGE (for File Generator and Edi- 
tor) which has powerful text-manipulating capabilities, (3) 
FINTOL for solving financial problems, and (4) MicroQuote 
to provide rapid access to information on securities traded on 
exchanges and over-the-counter. FORTRAN, APL, and Pas- 
cal are also available. 

Become a Wall Street wonder 

Over 32.000 stocks, bonds, and options are available in the 
MicroQuote database. Trading information is updated daily 
and, for the analyst who relies on charting historical data, 
prices and volumes are available back to January 1, 1968. 
Press the buttons with the MicroNet system and you can im- 
mediately become informed on your favorite stock's cur- 
rent and historical prices (high, low, and closing), dividends, 
earnings per share, ratings and shares outstanding. If bonds 
are more to your liking, you can obtain information on yields. 






76 









maturity dates, option information, Moody's ratings and ex- 
ercise prices. 

Cost for the use of MicroQuote is S5 per hour of connect- 
time. a per-access fee of SI for each use of MicroQuote, plus 
additional transaction fees based on the amount of informa- 
tion requested. For example, if you requested a list of 25 
issues, a 25-cent charge is applied. Daily, weekly and monthly 
price and dividend sets cost 5, 10 and 25 cents for each set, 
which supplies date, volume, high/ask, low/bid and close 
prices. If you wanted to examine a particular stock issue in 
detail, the charge would be SI. 25. 

A wide assortment of games— Space War, Star Trek, 
blackjack, chess, golf, craps, and football — is also available 
to keep the subscriber entertained. 

MicroNet users are permitted to store up to 64 kilobytes of 
their own data on the system. However, those files must be 
accessed at least once every seven days or they wil] be deleted. 

An interesting and innovative service offered by MicroNet 
is the opportunity to market software via the personal com- 
puter through two approaches. The first approach is for 
software guaranteed by CompuServe, MicroNet' s parent. 
Vendors will sell their tested software to CompuServe on a 
direct or royalty basis, A user finding this particular software 
beneficial to his business or interests can test the program on 
MicroNet and then purchase it using his credit card. The pro- 
gram would then be downloaded from CompuServe's main- 
frame to the personal computer. In a second approach, users 
will have an opportunity to test programs available from soft- 
ware retailers. In this case, CompuServe will act as a retail 
outlet, renting space on its network to software merchants. 

A Feedback system is available for subscribers who desire 
user guides and reference manuals for MicroNet programs 
that are not self-documenting. 

Electronic mall 

MicroNet' s electronic mail system relies on a bulletin- 
board format. The user places a message on the bulletin 
board using his personal computer. But, unlike other bul- 
letin boards, on this one. only the person to whom the 
message was addressed can receive it. Subscribers using 
this mode must scan the bulletin board as they enter the 
system to see whether any messages have been posted for 
them. 

A variation of personal-computer CB is also available from 
Micronet. A subscriber offers his "handle" or nickname and 
selects the channel he wishes to participate in. He is then in- 
formed of the number of other subscribers on the same chan- 
nel and can then choose merely to "listen" via his CRT dis- 
play or to take an active role. Needless to say, a crowded 
channel on a computer display is as unintelligible as a group 
chatting over a jammed CB voice channel. 

To join the MicroNet set, you add a modem to your per- 
sonal computer and set it for 300 baud. Request and return a 
service application to CompuServe's Personal Computing 
Division, 500 Arlington Center Blvd., Columbus, OH 43220. 
Your VISA or MasterCard credit card number is requested. 
You will then receive by return mail a user kit containing a 
user identification number, a secret password, a local net- 
work telephone number (if there is one) and basic documen- 
tation of the MicroNet system. Then to make life easier for 
you and to achieve compatibiltiy between the MicroNet 
system and your personal computer, a MicroNet Executive 
program is loaded into your computer at no charge. Billing 
for connect time, other surcharges, and any software pur- 
chases will be done through your charge card. 

Lockheed's Dialog 

Lockheed's Dialog, started in 1972, now provides access 
to over 100 databases which cover subjects including science, 
technology, literature, arts, business and finance. A sub- 
scriber can search over 40 million records including magazine 
articles, conference proceedings, legislative documents, 






"* THE SOUBCf. "~ 

ADVANCED APPLICATIONS A PBOGRAKS DATA ADAPJR 

A3PSCHED.ILES, DATA AIR5CMED 

MnuKOENTS (UIDATED FSEUUtTlTLVI DATA AMU II 

ASTROLttT LIBRART DATA A5TK0-LIB 

AKARE FINANCIAL SERVICE DATA AFS 

SUSINT.S5 » FINABLE DATA BUDEI 

CLASSIFIED ADS 1 SyUETIH BOARD ............. DATA CLAS5I 

CONSUME* INFORMATION, ...DATA CUNSlffl 

MOSS I-ASSEMBL£1S IHF0 X-ASSESBLEBS 

DINIHG OUT, .(HASHING™, O.c.).... RESTED 

DISCOUNT 5N0PP.HG SEBVICE (HONEJ SAVERS] DATA 6UCTS 

EDUCATtOH DATA EDDCAT 

ENERGT SAVINS HENS A TIPS, ...... .ENERGY 

FINANCIAL NEHS DAIA BliOEl 

GAKE5... DATA GAMES 

»0K£ ENT£8TAI«NT DAIA lUKENT 

INFORMATION ON PEKAWD, ......DATA 100 

HA.LCALl., .0ATA HAILCALL 

HAIL DELIGHT .,.,,. ...INFO DATAPOST 

NEB TONS TIKES N£« SUHPMt DATA NTTHS 

NEW roR< TIKES CDK5UHER DATA BASE.,.,. ........... NTTCDB 

POLITICAL ACTION BfPOlT.,... ..M.TA MB 

PEHS0HAL CALIWAI? 1 NOTEBOOK ..DATA PERSON 

PERSONAL FIHAIVCE ........0ATA PERSF3 

SCIENCE B ENGINEERING 0ATA SCIEND 

SflF-PERCEPTION DATA ESP, DATA LORE 

SPORTS*... DATA SPORTS 

SUGGESTION BOX......... TJATA SUGBOI 

TSAVEL CLUB DATA TRAVEL 

UHITED PRESS INTERNATIONAL (DPI). .DATA OANEHS 

USER CIRECTWtr.. DAIA USED1R 

roiCEOBAK ...DATA tOICEBBAH 

HEATHEN DATA HEATHB 

WISDOM OF THE AGES ....LflSUUK 



SOME OF THE SERVICES offered by The Source to users of personal 
computers. 

technical manuals, patents, newspaper articles, directories 
and dozens of other sources. 

Put another way, Dialog offers the equivalent of a vast 
library to the owner of a personal computer to use in the 
comfort of his home. 

What are the costs? There are no startup, no initiation, or 
monthly fees. You pay only for the time on the system plus 
the communications-lines fees. For example, if you were re- 
searching a paper on Computer Programming and Computer 
Systems, you would access INSPEC {which includes Physics 
Abstracts, Electrical and Electronics Abstracts and Com- 
puter and Control Abstracts); the cost would be $55 per on- 
line hour. If you were interested in a specific government- 
funded research and development program, you would 
browse through the NTIS (National Technical /nformation 
Service) which has a fee of only S35 per on-line hour. Accord- 
ing to Lockheed, a typical search might require 10 to 15 
minutes time for a cost of SI0 to S20. This includes TymNet 
or TeteNet charges. 

When you think about it, it's a fantastic bargain. The data- 
bases include periodicals going back ten years or more, with 
the most current issues available. Think of the time, gas. and 
parking fees involved in visiting your local library to search 
through their files manually. When you locate the specific 
items, the librarian would require additional time to locate 
some of the outdated material (if the library is large enough to 
maintain a lengthy file of the publications you require). 

An active training program is available for new users at a 
cost of $65 per person for a one-and-a-half day session and 
$25 for a half-day refresher course. However, whether you 
sign up for these courses or not, you will be entitled to re- 
ceive a credit of up to $100 for practice lime. (Communica- 
tions costs are not included.) 

To initiate service with Dialog, an order form may be ob- 
tained from Lockheed [nformation Systems, Dialog Market- 
ing, 3251 Hanover Street, Palo Alto. CA 94304. There is no 
minimum amount of on-line time to be contracted for and the 
service may be cancelled by the subscriber upon 30 days 
notice. During the first month of service, up to $100 will be 
credited towards search efforts since training will be taking 
place. Dialog service is available 1 10 hours a week, from 
Monday to Saturday. 

Just a sampling of the subjects comprehensively covered 
by the Dialog databases includes: accounting, acoustics, ad- 
vertising, aerodynamics, agricultural engineering, aircraft, 
anatomy, art and art history, astronomy, banking, biology, 
biophysics — and that's only part way through "B". With 
your home computer linked to an enormous on-line system 
such as Dialog, you have access to a vast library that would 
be the envv of a multimillionaire! R-E 



o 
o 

CO 
m 

J3 




Computers cannot act on their own- 
Here's a discussion of several of the 



-they have to be told what to do. 
languages used to instruct them. 



IF YOUR RICH UNCLE PASSED AWAY AND LEFT YOU A MULTI- 

mitlion dollar IBM computer, it probably wouldn't do you 
any good (unless you sold it). All you would possess would 
be a well -de signed piece of computer hardware unless he 
also left you the software (programs) to tell the machine 
what to do. 

The computer is a machine. It doesn't understand the 
English language. Yet it is capable of performing an end- 
less number of tasks, involving lengthy calculations and 
complex procedures. And the computer can respond to 
a computer language, so the obvious step is to develop a 
language that can be understood by humans and somehow 
converted to the language a computer can follow. 

A computer program is a set of instructions that tell the 
computer what to do. A computer language defines the 
rules of grammar and vocabulary for writing instructions. 
If you don't follow the rules, the computer cannot under- 
stand the instructions, and it will be unable to perform its 
assignment. 

A statement, or instruction , in a computer program, is a 
string of elements from an alphabet that includes letters, 
digits and symbols. A set of rules, or syntax, establishes 
the form of each statement which conveys a specific oper- 
ational meaning or semantics. Thus a computer language 
includes the alphabet, syntax and semantics. 

Computer languages in use today can be grouped into 
three broad categories: machine languages, assembly lan- 
guages, and problem-oriented languages. Both machine 
and assembly languages are considered low-level languages 
while a problem-oriented language is concerned high level. 



Machine language 

The most elementary language is machine language 
since it is the only language that the computer understands 
directly; any other language is "foreign" to the computer 
and thus it will not recognize or execute proper commands. 
Machine language is written with the computer's hard- 
ware or design configuration in mind so the programmer 
must be well aware of how the machine works. Because 
the vocabulary and grammar rules are rather limited, ma- 
chine language is considered simple. However, because 
of the limited vocabulary, a fairly long program is required 
to lead a computer through a relatively simple assignment. 

A machine-language program consists of a list of instruc- 
tions in binary form to direct the computer to perform an 
operation or a series of operations such as add, multiply, 
read, write, or store. For the programmer's convenience, 
decimal, octal, or hexadecimal numbers may be used and 
then converted into binary numbers inside the machine. 
The operation to be performed is given by a code that di- 
rects the computer to perform a specific operation and also 
supplies the operand, which is the quantity to be operated 
upon. Instructions in machine code are binary numbers, not 
letters or words. A series of binary numbers representing 
a very small part of a machine-code program would look 
something like this: 

Operation Code Operand 1 Operand 2 

01011001 01001 100 noiioio 

To perform a simple addition of just two numbers would 
involve the above listing of l's and 0's, in the binary Ian- 




guage that makes the computer perform. In 
enormous sequence of O's and I 's required to perform a 
complex calculation! 

Obviously, the computer programmer who attempts to 
prepare a lengthy program in machine language will be 
prone to making errors since it is a tedious and tiresome 
task. The task is somewhat lessened with the aid of an 
octal or hexadecimal program that accepts the program- 
mer's inputs in octal or hexadecimal (special numbering 
systems that are more intelligible to humans than binary) 
and converts them to binary. 

The advantages of machine- language programming are 

(1) the ability to instruct the computer directly and (2) the 
low requirement for supporting software or memory. The 
disadvantages include ( 1) the need for the programmer to 
have full awareness of the machine's hardware structure, 

(2) the lengthy and tedious effort involved in writing the 
program and (3) the lack of flexibility in using a program 
written for one computer on another type. For example, 
a machine-language program written for a Motorola 6800- 
based computer cannot be applied, without extensive 
modifications, to a computer using an Intel 8080 CPU. 

Perhaps the greatest drawback to machine-language 
programs is their lack of intelligibility to non-computer 
users. A detailed machine-language program, with its 
lengthy series of O's and l's — or even their octal or hexa- 
decimal equivalents — has no meaning to the student, en- 
gineer, businessman, or layman eager to apply the com- 
puter to his specific applications. Indeed, even a profes- 
sional machine-language programmer has quite a task 
keeping track of the meanings of the machine code. 

Assembly language 

To make computer programs easier to comprehend, sym- 
bolic languages were developed. Such a language makes 
use of letters or names for instructions, data and addresses. 
These names or "mnemonics" refer to the terms they 
represent so a computer user can, by association, relate 
the term to the function. An example of mnemonic sym- 
bols in everyday use is DOD for Department of Defense 
and IRS for Internal Revenue Service. Only three letters 
are used as shorthand identification, yet most people 
know immediately what they represent. 

Not all instructions are as easy to remember as ADD, 
SUB, or AND. But it is not too difficult for the program- 
mer to associate LA with "load the address" or P to punch 
a card. Such use of symbolic code rather than a lengthy 
string of ones and zeros was the first major step to bring 
computer-programming capability to the non-professional 
programmer. If we wanted to have the computer calculate 
X= A+B, where A=3 and B=5, in assembly language, 
we would use the assembler instructions listed in Table I. 
TABLE 1 



Location 


Operation 


Operand t 


Operand 2 


Comments 


Begin 


LDA 


REG 6 


B 


Load B into regis- 
ter 6 




ADD 


REG 6 


A 


Add A to register 6 




STA 


X 


REG 6 


Store register 6 
at X 



The symbolic instructions listed in Table 1 would be 
translated into machine-language form by the assembler. 

Now a non-professional programmer can write what's 
known as a source program, using symbolic language, 
with instructions or statements to guide computer activ- 
ities. Next, a processing step is required to translate the 
source program (easy for a human to write and under- 
stand) into an object program, which is a machine-language 
program that the computer can understand. The program 
that accomplishes this task is called a translator. Its out- 
put, the object program, is what the computer requires to 
direct its operation. 



of machine language but the vocabulary is different. Since 
a computer is still being directed, the operations available 
and the sequencing are unchanged. However, mnemonics, 
rather than numbers, are used in preparing the program. 

Symbolic languages make computer-program prepar- 
ation easier, since terms, rather than numbers, are used to 
relate to the problem-solving needs. 

A profound advantage of symbolic language is the ability 
it gives one type of computer to process programs written 
in many different languages, provided a translator pro- 
gram is included with each language. This means that one 
computer can handle programs written in either BASIC 
or FORTRAN (to be described later), as long as a separate 
translator is available to convert each into the computer's 
machine-language code. 

This first step to make programming a bit simpler is 
called assembly language, machine-oriented language, or 
low-level programming language. Although symbolic 
notation makes program- writing easier than straight binary 
coding, it takes about as many symbolic instructions to 
write a program as machine language does. Stated another 
way, there is a one-for-one conversion of language instruc- 
tions. Thus, the assembly -language programmer still must 
write lengthy instructions and must be familiar with all the 
peculiarities of the computer he is programming. For com- 
plex programs, many of the abbreviated mnemonics will 
not take convenient comprehensive form and will require 
extensive commentary to keep track of all the definitions 
of terms. 

The translator that converts the assembly- language 
(source) program into the computer object program is 
called an assembler and is usually located in the com- 
puter's memory. As the source program, written in sym- 
bolic language, is entered into the computer, the assem- 
bler converts each symbol into machine-language form 
(or the object program). At this stage, the computer is 
only recording the object program in its memory, or onto 
punched paper tape, magnetic tape or disk. When the 
translation task is completed, the object program can be 
entered in its entirety into the computer; now the com- 
puter can understand the instructions and data, and can pro- 
ceed to execute the program. 

Assembly language is an improvement over machine lan- 
guage, but is still machine-dependent. Every type of com- 
puter requires its particular assembly language. 

Problem-oriented languages 

The next step in program design makes the computer 
hardware (and type of computer) relatively unimportant 
with respect to the task to be performed. This type of lan- 
guage is known by such names as: "problem-oriented," 
"procedure-oriented," or, simply, "high-level." It ap- 
proaches the programming problem from the viewpoint 
of the goal to be achieved, rather than the specific machine 
that will achieve it. 

Broadly speaking, there are two types of high-level 
language — compilers and interpreters. Compilers will be 
considered first. 

A compiler allows a program to be written in English- 
like terms and translates it directly into machine language. 
With it, a single statement, such as "PRINT," can cause 
a whole series of machine-language instructions to be 
executed. From the human point of view, a compiled lan- 
guage is much more efficient than assembly language. 

As with an assembler, the compiler first translates the 
source-language program into an object program before 
running it. A program, that originally has been written using a 
compiler cannot be run unless the entire program (or a com- 
plete section of it) has first been translated (compiled) into 
machine code. Here's how a program would be compiled on 
a large computer system (smaller systems use floppy disks 




79 



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rather than punch cards): 

First the program is laid out, and debugged to the great- 
est extent possible (getting the bugs out of an already com- 
piled program is not the simplest task in the world), using 
coding sheets. Then, assuming that a punch-card system 
is being used, a keypunch operator punches or codes one 
card for each line on the coding sheet. The complete set 
of such cards is called the "source deck." 

Then, with the compiler already in the computer's mem- 
ory, the program is fed into the computer one card at a 
time. After all the cards have been fed in, the program is 
compiled, and a new set of cards, containing machine-lan- 
guage instructions, is generated. This set is known as the 
"object deck." Since one "source" card may require 
several machine-language instructions to be carried out, 
the object deck contains many more cards than the ori- 
ginal source deck. 

After compilation, the code from the object deck is 
loaded back into the computer, and the program can be 
run. 

The other type of high-level language we'll discuss is 
the interpreter. Most of the B ASIC's used with small com- 
puter systems are interpreters. Interpreters, like com- 
pilers, allow programs to be written in an English-like 
form, but operate somewhat differently internally. The 
most significant difference is that no compilation takes 
place and that the source code is always accessible. 

An interpreted language translates instructions into 
machine language as the program executes — in real time- 
rather than "predigesting" them all at once, as does a 
compiler. Because an interpreter is constantly "inter- 
preting" (or translating) as well as actually executing the 
program, it tends to run more slowly than a compiled lan- 
guage. Furthermore, the interpreter retains no memory 
of what it has interpreted so, even if it has already executed 
a certain routine a hundred times, it must interpret it anew 
when it encounters it for the hundred-and-first. This makes 
for an even greater reduction in speed. 

Interpreters have their advantages, though. Because 
you are always working with source code, it is simple to 
modify a program should a change be necessary. A pro- 
gram can even be stopped while it is running, altered, and 
the run continued. This is an impossibility if you are using 
a compiled language. Also, while a compiled program 
may occupy much less memory than an interpreted one, 
the compiler itself may take up so much room in a small 
computer that it would leave little or no memory space for 
the program it was intended to run. 

Machine and assembly languages are designed to match 
specific computers, and bear no relation to the applica- 



tions the computers are intended to perform. Problem- 
oriented, or high-level, languages disregard the hardware 
aspects of the computer and concentrate instead on the 
applications. To simplify programming, it was desirable 
to develop different languages for different applications. 
Languages have been developed for mathematical and 
scientific needs, for business procedures, for text editing, 
and for other specialized needs. Only one problem-oriented 
language has been developed as a universal language to 
replace all others: the IBM PL/1 or Programming Lan- 
guage/1. 

The premise was that scientists, businessmen, engineers, 
and computer experts could program nearly everything 
they needed with this language. Unfortunately, the lan- 
guage is so complex that few programmers can handle it. 
Secondly, a powerful computer is required to use the pro- 
gram. And finally, it turns out that the scientific program- 
mer using PL/1 involves himself only with the scientific 
portion while the business programmer only identifies with 
the business section. It may well be that the goal of an 
ideal computer language is not unlike that of a universal 
language for speech around the world. Wouldn't it be con- 
venient to have one language spoken and written through- 
out the world? No need for guide books, language-phrase 
books, language courses for the traveler — but as obvious 
as the need appears, the prospect of a universal language 
is far distant. So too, perhaps for a universal computer 
language. 

Advantages of high-level language 

What are the advantages of high-level languages? Pro- 
grams are shorter, easier to write, and debugging (locating 
errors) is simplified. Programs written for a particular 
application can be supplied to users around the world, 
regardless of the computer they have, as long as a compiler 
or interpreter is available for the language used. And, of 
course, there is no need for the programmer to be con- 
cerned with the inner workings or details of his computer's 
hardware or machine language. 

Then why are low- level assembly- or machine- languages 
still in use? High-level languages require considerable 
memory and programs run slower since a translation pro- 
cess is involved between the human-oriented and machine 
language. Often the compiler is expensive and requires a 
large amount of memory. If an interpreter is used rather 
than a compiler, translating each statement and executing 
it, less memory is required. The tradeoff is a loss in effi- 
ciency since translation must be performed every time the 
user runs the original program. 

Which is best? For the non-professional programmer, 
high-level languages are much simpler to prepare and use; 
programs are relatively easy to comprehend from the 
symbols involved. Assembly and machine-language pro- 
grams, when properly prepared, can make the computer 
perform faster; also, programmers familiar with the par- 
ticular strengths of a computer's hardware can make the 
computer "do tricks" and thus operate more efficiently 
than would be possible with general-purpose high-level 
programs. Even today, assembly and machine languages 
offer efficiency unmatched by high-level languages. 

Popular high-level languages 

High-level languages, or problem-oriented languages, 
can be general-purpose, or can be specifically tailored for 
applications such as engineering, education, banking or 
process control. Over a thousand languages are in exis- 
tence, some used only by a handful of specialists and others 
enjoying widespread use by a large number of computer 
users. 

Among the most popular computer languages are: 
ALGOL (A/gorithmic Language)— a math and science 
language in common use in Europe. 



APL (A Programming Language}— a language to handle 
long strings of numbers or letters with ease. 
BASIC (Beginner's Ali-Purpose Symbolic instruction 
Code}— a language developed to introduce students to 
computers; simplicity and ease of use highlight this lan- 
guage. Widespread use with personal computers. 
COBOL (Common fiusiness-Oriented Language)— the 
original language designed for the non-professional 
programmer for business, rather than scientific, appli- 
cations. 

FORTRAN (Formula Translation Language}— Probably 
the most widely used language. Although originally in- 
tended for scientists, it is in widespread use for business 
applications. 

USP (List Processing) — a language developed by a group 
at MIT to handle list processing. Lists are finite sequences 
that can appear in a large variety of structures in the form 
of numbers, letters, or even computer words. 
Pascal — an extended version of ALGOL developed for 
teaching structured programming to students. 
PL/1 (Programming Language/T)— a complex language 
combining the advantages of COBOL, FORTRAN, and 
ALGOL. The language contains more features than any 
other language; however, because of its complexity, it 
is difficult to learn and apply. 

RPG (fleport Program Generator) — a language for re- 
questing and defining reports. 

Languages in detail 

Wouldn't it be ideal if all computers understood instruc- 
tions written in the English language? Yes, it would, but 
there would always be problems. Human languages are 
extremely complex and yet imprecise. Words don't mean 
the same thing to everyone. For example, "watch" may 
indicate "observe" to one person and "timepiece" to 
another. With computers, words and instructions must be 
exact, without ambiguities to confuse the computer. 

High-level, or problem-oriented, languages are a good 
compromise for efficient communications between humans 
and the computer. It has been estimated that well over 
1,000 high-level languages have been developed; perhaps 
200 enjoy some form of popularity. 

Why so many languages? High-level languages are in- 
tended to handle problems and thus deal with a multitude 
of applications. While many languages have a rather broad 
appeal and application, there always seems to be a reason 
for programmers to develop a specific language for a spe- 
cific need. There are high-level languages, for example, 
exclusively tailored for numerically-controlled machine 
tools, electronic circuit design, hydraulic system analysis, 
graphical analysis and other such specialized applications. 

ALGOL 

ALGOL (Algorithmic Language) was developed in the 
mid-1950's for scientific and mathematic applications. 
ALGOL is much more popular in Europe than in the U.S. 
and is well respected as a powerful language capable of 
handling very complex programs. 

One version of ALGOL of particular significance is 
the "publication" version which many computer scien- 
tists use to describe new programs they have developed. 
Thus, there are many programs published in ALGOL even 
though the program authors or potential users do not have 
the sophisticated hardware to run or test the programs. 
The publication version of ALGOL is based upon the type 
faces generally available to printers and thus includes up- 
per and lower case letters, methods to indent lines, and 
bold-face type. 

The language's power and versatility are assets which 
are hampered by the need for a relatively large, slow, and 
expensive compiler. Programs in ALGOL are separated 
into blocks, with smaller called-subroutines or procedures. 

APL 
In I960, Ken Iverson of IBM developed APL (A Pro- 



gramming Language) as a notation for describing algo- 
rithms. (An algorithm is a prescribed set of well-defined 
rules or processes for the solution of a problem in a finite 
number of steps.) Based on a series of symbols for logical 
and mathematical functions, APL is easy to learn and 
requires relatively few characters to define complex oper- 
ations. It is used in applications ranging from complex 
mathematical and scientific problems to text editing and 
computer-assisted education. 

APL's major attraction is its powerful problem-solving 
capability coupled with a high degree of interactivity. This 
allows top-level managers, such as businessmen and financial 
analysts with key decisions to make, to "have a con- 
ference" with their computers using APL. Since the lan- 
guage is easy to learn and use, these busy managers do not 
require extensive training nor added staff to handle the 
program. 

APL makes use of several unusual symbols, such as an 
upside-down T, and thus special terminals are required for 
APL to put these symbols into the machine. APL is not a 
scientific language, but is considered more of a manipu- 
lative language for handling long strings of numbers or 
letters; it's ideal for text editing. The text of an article or a 
book can be fed into a computer using an APL program; 
the manuscript can be rewritten or altered with spelling 
corrections or hyphenation, and then retrieved from the 
computer in its new format. Many modern automated 
printing and publishing firms use APL for such automatic 
typesetting applications. 

APL, as well as BASIC, are languages based on inter- 
preters rather than compilers. This means that programs 
can be written, tested and debugged rapidly. 

The APL language is used by large firms as a powerful 
analytic toot for long-range planning. 

BASIC 

BASIC, Beginner's All-Purpose Symbolic /nstruction 
Code, was developed at Dartmouth College in 1965 as a 
language for introducing students to computer science. 
The project was supported by a grant from the National 
Science Foundation and was managed by Professors 
Kemeny and Kurtz. BASIC was originally intended for 
use on a time-sharing computer. 

The object of the project was to come up with an easy- 
to-use computer language; its success has made it the most 
popular language among non-professional programmers 
and computer hobbyists. It is a language intended for an 
amateur programmer who has a problem, wants to use 
a computer to solve it, wishes to prepare his own program 
rather than hire a programmer, and doesn't have a large 
budget. 

A major advantage of BASIC (and APL) over other 
languages is its use of an interpreter rather than compiler. 
Programs prepared by an amateur can be inspected, modi- 
fied, debugged and corrected without tedious recompil- 
ation. BASIC can accept program changes with a minimum 
of effort on the part of the programmer. Another advan- 
tage of BASIC is its interactivity. 

BASIC is easy to learn because it has a limited vocabu- 
lary compared to FORTRAN, COBOL or other popular 
languages. The primary statements are arithmetic, pro- 
gram control and input/output. Every language consists 
of a set of characters; BASIC uses the 26 letters of the 
alphabet, all ten decimal digits (0 to 9), and fewer than two 
dozen additional characters (arithmetic operators, punctu- 
ation, etc.). 

Here are some of the fundamental rules that were estab- 
lished in the original Dartmouth BASIC: 

• A line can include only one statement. 



O 

I 

S 
m 



■ Each statement must include a line number followed 

by a keyword. «> 

• Statements or instructions are performed in order of 



TABLE 3— HEX & BINARY Represents 
lions of 8080 "addition" machine code: 



line number, 
• A BASIC program must be completed with an END 

statement, 
A keyword indicates the type of instruction such as LET, 
PRINT, DATA, END, OR REM. REM (for REMARK) 
is a comment to inform or remind the user of the program 
content but is not acted on by the computer. LET takes 
the form of LET X = A + B + C where LET means the 
value of the expression A + B + C replaces the variable X. 
PRINT, appearing by itself, simply allows a line to be 
skipped on the printer or display device; PRINT, followed 
by words enclosed in quotation marks, commands the com- 
puter to display the words. For example, PRINT "THE SKY 
IS CLEAR" would result in THE SKY IS CLEAR being dis- 
played or printed out. The instruction READ orders the 
computer to obtain data from within the program and store 
it in a particular memory location. The READ and DATA 
instructions are used together in this manner: the first 
variable listed in the READ statement corresponds to the 
first number in the DATA statement. A simple BASIC pro- 
gram to add 2 plus 3 will demonstrate and clarify how these 
statements relate: 





TABLE 2 


10 REM A SIMPLE ADDITION PROGRAM 


20 READ A. B 




30 LET X = A + B 




40 PRINT X 




50 DATA 2, 3 




60 END 





The REM comment allows us to identify the program 
content. The READ instruction sends the computer to the 
DATA storage where the first variable, A, corresponds to 
2 and the second variable, B, has a value of 3. The LET 
statement means that the expression A + Bor2 + 3or5 
replaces X. Then the PRINT instruction directs the value 
of 5 to be displayed on the output. The END statement 
concludes the program. For comparison purposes, the 
same problem listed in Table 2 is given again in binary and 
hexadecimal machine code for an 8080-based computer in 
Table 3. 

There are quite a number of versions of BASIC avail- 
able today with no two types exactly interchangeable. 
Thus a BASIC program written for an Apple computer 
won't necessarily work on a Radio Shack TRS-80. The 
programs are similar enough so that even an amateur can 
understand the differences; but the lack of conformity is 
frustrating when the program for one computer is wanted to 
run on another and extensive reprogramming is required, 
ming is required. 

There are several reasons why programs written in one 



Hex 


Binary 


AF 


10101111 


3E 


00111110 


02 


00000010 


06 


00000110 


03 


0000001 1 


80 


10000000 


21 


00100001 


88 


10001000 


13 


00010011 


77 


01110111 



TABLE 5— ADDITION of two 
numbers In FORTRAN: 




A=2+3 
WRITE 10.A 
10 FORMAT (12) 
END 



BASIC will not run when transcribed into a machine that 
uses another BASIC. First and foremost is the fact that 
some BASIC'S have commands that others haven't. The 
reason for this is often related to the amount of memory 
available. For example, one of the first BASIC'S available 
for home computers was known as Tiny BASIC. In its 
original form, Tiny BASIC had no string capability and 
could not handle trigonometric functions. Some versions 
of it only worked with integers and no floating-point cal- 
culations were possible. These early versions generally 
needed only 1 or 2K of memory. But, as memory got 
cheaper, functions were added to these Tiny BASIC'S 
and programs written with the updated versions were in- 
compatible with the earlier ones. 

Today, there are still more variations of BASIC. The 
first distinction is between integer BASIC and floating- 
point BASIC. Integer BASIC is generally faster, and is 
good for video graphics applications. A computer that of- 
fers both integer and floating-point BASIC'S is the Apple 
II, and the incompatibility between the two languages is 
clearly demonstrated when one tries to run an integer 
BASIC program in the floating-point mode. For example, 
INPUT statements in floating-point are followed by a semi- 
colon, while in integer BASIC, they are followed by a 
comma. Strings are handled differentiy, too. Integer BASIC 
simply has no string functions (e.g. RIGHTS, LEFTS 
MID$, STR$, etc.). These functions are present in the 
Apple floating-point BASIC, and, are similar to those 
used by North Star basic. 

Another thing that makes BASIC'S incompatible is the 
way they use abbreviations. The Microsoft BASIC'S use 
a "?" as an abbreviation for the PRINT statement. North 
Star BASIC uses a "!" and Radio Shack Level 1 BASIC 
uses "P." Not all versions of these languages convert the 
abbreviated form back to the full word when the program 
is listed, so that trying to transcribe a program with these 
abbreviations for a noncompatible machine could be quite 
disastrous. 

If you stick to using the full word and avoid abbrevi- 
ations, you'll find that there is a subset of BASIC com- 
mands that is common to almost all personal computers. 
Table 4 contains a list of 41 commands that are fairly uni- 
versal. However, even though a command may exist in 
two different BASIC'S, it may not do the same thing in 
both. An example of this is the GET command. In Apple- 
soft BASIC this command tells the computer to wait for 
the user to input data from the keyboard. The computer 
waits for a key to be pressed and then returns the value 
of that key. In PET BASIC, when the GET command is 
encountered, the computer also looks at the keyboard for 
a key closure. However, if no key is pressed, it immedi- 
ately returns the value 255 instead of just waiting for a key 
to be pressed. This means that programs must be written 
a little differently for each case, as illustrated below: 

In Applesoft the GET statement would be used like this: 



10 GET A$ 

To get the same action (without having the computer return 
the value 255) in PET BASIC you'd have to write: 
10 GET A$:IF A$=" " THEN l(f 

This is a perfect example of how two BASIC'S having 
the same commands can result in programs that are incom- 
patible with each other. 

TABLE 4 



ABS 


AND 


ASC 


ATN 


CHR$ 


COS 


DATA 


DEF 


DIM 


END 


EXP 


FN 


FOR 


FRE 


GET 


GOSUB 


GOTO 


IF 


INPUT 


INT 


LET 


LIST 


LOG 


NEW (or SCR) 


NEXT 


NOT 


OR 


PEEK 


POKE 


PRINT 


READ 


REM 


RESTORE 


RETURN 


RND 


SIN 


STEP 


TAB 


TAN 


THEN 


TO 





Assuming that the BASIC'S do have compatible com- 
mands, you're Still not out of the woods. The reason is 
that some commands link BASIC to machine language or 
specific memory locations; notably PEEK and POKE. 
These commands are available in most BASIC'S except 
those from Texas Instruments and Hewlett-Packard. 
However, because different computers have organized 
the use of memory differently, it is not always possible 
to use programs that have PEEK and POKE statements 
in them directly. For example, if the POKE statement is 
used to temporarily store a number in memory for later 
use on one machine we could be in serious trouble using 
it in another. In the Apple, memory locations around 768 
are available for use by the programmer, while in the TRS- 
80 this area of memory is used by the operating system. So 
before using these commands, be sure you know a little 
bit about how both your computer and the one the program 
was written on are organized. 

Finally, different computers have additional commands 
designed specifically for their own hardware configuration. 
The Apple-II for example has several commands, designed 
to be used in its low- and high-resolution color graphics 
modes, that would be meaningless on another machine. 

FORTRAN 

One of the earliest and still very widely used, high-level, 
problem-oriented languages is FORTRAN (Formula Trans- 
lation). Developed in the mid-1950's by a group of several 
firms headed by Jim Backus of IBM, FORTRAN took 
three years of effort involving some 25.000 lines of detailed 
machine instructions. 

FORTRAN is always compiled, never interpreted. 
FORTRAN compilers are available for just about any 
computer manufactured in the world. 

As its name implies, it was intended for use on mathe- 
matical and scientific formulas. However, its applications 
became more diverse due to its early acceptance at col- 
leges and universities where computers were introduced 
to the student body. As graduates with knowledge of com- 
puters and the FORTRAN language went into the business 
world, they proceeded to solve business problems with 
variations of FORTRAN. 

In a steady, evolutionary manner, FORTRAN has been 
expanded into an extremely powerful language and its 
name has been modified to FORTRAN I, FORTRAN II, 
FORTRAN IV and FORTRAN 77. A high degree of stan- 
dardization has taken place over the years so that a pro- 
gram written in FORTRAN IV will perform properly with 
most FORTRAN IV compilers. 

FORTRAN, although geared for complex mathematical 
assignments, is rather straightforward in its approach. 
For example, to solve X = A + B when A = 3 and B = 5, 
the instructions would read A = 3,B=5,C = A + B, 
STOP. These source instructions would, in turn, be trans- 



lated by the FORTRAN compiler into machine language 
to execute the step to solve the problem. An actual FOR- 
TRAN program is listed in Table 5. This program is iden- 
tical to the BASIC program listed in Table 2. 

A compiler to handle a FORTRAN IV language is quite 
extensive. Not only must it handle a considerable number 
of mathematical operations, but it must perform such math 
functions as trig, square roots, exponentials, complex 
numbers, and logarithms. It must also manage to cope with 
strings of numbers and letters and lengthy mathematical 
arrays. 

In FORTRAN, a number can be represented as a fixed 
point or as a floating point. A fixed-point number must be 
an integer or whole number and can be positive or nega- 
tive. A floating-point number is similar to scientific nota- 
tion where "number" may be expressed as a number from 
I to 10 multiplied by some power of ten; 580 could be 
expressed as 5.8 x 10". A floating-point number always in- 
cludes a decimal point; a fixed-point number does not. 

FORTRAN includes provision for two other types of 
numbers: constants and variables. A constant maintains 
the same value during the program execution while a vari- 
able can be assigned different numerical values while com- 
putations are being performed. The name assigned to a 
variable can include up to six characters and is selected, 
where possible, by the programmer for his ease in remem- 
bering its meaning. For example, SQRTF signifies square 
root. 

The basic mathematical symbols for FORTRAN oper- 
ations are: 

Addition + 

Subtraction - 

Multiplication * 

Exponential ** 

Division / 

For example, to indicate 2 raised to the 3rd power, we 
use 2**3. As with standard math notation, parenthesis are 
used for groupings; For example: (2 + 3) raised to the 3rd 
power is written as: (2 + 3)**3. 

Input-output statements in FORTRAN are expressed 
as READ, WRITE, PRINT, PUNCH and FORMAT (this 
describes how the output information should be accepted). 
A GO TO statement informs the computer to execute an 
instruction or statement other than the next statement in 
sequence. An IF statement provides for a conditional trans- 
fer of control, or proceed to another statement if specific 
conditions are met. An END statement informs the com- 
piler that the program is completed. 

COBOL 

COBOL (Common Business Oriented Language) was 
developed in 1960 by the Department of Defense together 
with users and manufacturers of computers. Its purpose 
was to handle relatively large volumes of business infor- 
mation for rather simple applications. The intent was to 
enable non-programmers such as accountants and clerical 
staff to express their business problems in English. For 
example, if a clerk wants to know the value of present stock 
in inventory, the COBOL statement would request "COM- 
PUTE STOCK VALUE," leaving no doubt of the mean- 
ing to the human. A COBOL compiler in the computer 
would convert the statement to the necessary machine- 
language instructions required to initiate the actions. 

The basic COBOL vocabulary consists of 250 key words; 
additional words can be created merely by specifying 
names for data and instructions. 

Scientific applications generally require complex steps 
and considerable calculations, but have few input and 
output demands. Business applications, on the other hand, 
demand considerable input and output with relatively little 
computation. COBOL is designed to handle extensive 
filing on punched cards, tapes or magnetic disks. 




63 




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Another significant difference between a scientific and 
business application is the repeated use of a particular 
program. Scientific programs may be developed for a par- 
ticular problem, used for awhile and then become obsolete, 
A business program, on the other hand, is often repeated 
and used over a considerable period of time; for example, 
a payroll program may be used every week for years with 
only minor modifications for tax-rate alterations. 

Since COBOL statements are expressed in a language 
very close to commonly-used English, its programs can 
be shared by many users with tittle chance for confusion. 
Every COBOL program has an Environment Division 
describing the computer used to compile the program and 
to run the program. Thus a COBOL program can be com- 
piled on one computer and run on another completely dif- 
ferent machine. It is also possible to interchange input and 
output equipment, a convenient feature since the program 
can be run even if the system printer becomes defective 
and a different model is the only available unit on hand. 

COBOL's major attraction is its ability to handle large 
amounts of records and data, making it ideal for reporting 
and record manipulation. In applications where complex 
calculations and business decision-making is involved 
with such record keeping, it is not unusual to use both 
FORTRAN and COBOL languages, separately of course, 
to achieve the required results. 

Since COBOL is intended for business applications, its 
language resembles a sequence of English words, used as 
variables for its mathematical applications. Thus, COBOL 
is concerned with rules for nouns, verbs and punctuation. 

A COBOL program consists of four elements or divi- 
sions: (I) Identification, which provides a name for the 
source program, (2) Environmental, which identifies the 
computer to compile the source program and run the object 
program, (3) Data, which defines the files of data to be 
worked with or prepared by the program, and (4) Proce- 
dure, which specifies the steps the computer will execute. 
Precise rules dictate the reference format (spacings, mar- 
gins, etc.) 

COBOL's English-like sentences make it relatively 
simple to describe the data to be used and the operations 
to be performed. Of course, a clear analysis of the prob- 
lem is necessary before the program can be written. 

A simple COBOL program to calculate 2 multiplied by 
3 might look like the program in Table 7. 

TABLE 6— ADDITION of two numbers in COBOL: 



Pascal 

Writing a large program is considerably harder than 
writing several smaller programs; thus, a large program 
requires detailed organization and systematic procedures. 
Structured programming is a technique used to handle 
such large projects as an airline reservation system or a 
fully automated warehouse. The objective of structured 
programming is to make program structure simpler using 
a series of simple sequences of operations; in this way 
errors can be precisely located and corrected before the 
entire lengthy program is completed. 

A language geared to structured programming is Pascal, 
developed in Switzerland in the early 1970s. The language 
is simple and efficient and its compiler is not complex, 
making it attractive for manufacturers of mini- and micro- 
computers. Its creator, Professor Wirth of Zurich, gathered 
together useful features and instructions from existing 
successful languages to simplify the task of writing large, 
complicated programs. For example, a Pascal program is 
closer to plain English than BASIC. 



TABLE 8— ADDITION of two numbers in Pascal 



{* ADDITION OF TWO NUMBERS IN PASCAL *) 
PROGRAM ADDITION (INPUT.OUTPUT) 

VAR SUM: INTEGER; 

BEGIN (' ADDITION •> 
SUM := 2 + 3; 
WRITELN (SUM) 

END. (* ADDITION *) 






ADD 2 TO 3 GIVING A 
MOVE A TO PRINTLINE 
WRITE PRINTREC 



Pascal is rapidly becoming a popular language among 
manufacturers of microcomputers and thus may eventually 
become a more common language for smaller systems 
and computer hobbyists than is BASIC. For comparison 
the same program written in BASIC in Table 2 is shown 
written in Pascal in Table 8. 

In summary, there are quite a number of computer lan- 
guages in existence today. The question of which language 
is best is no different than asking a TV serviceman which 
of his tools is best: the VTVM, the scope, the VOM, or 
perhaps even his diagonal cutters? A computer language 
is also a tool. 

For a particular business application, COBOL may be 
the first choice, while FORTRAN wins out for an engi- 
neering problem. With limited computer size, BASIC may 
turn out the only alternative for a particular problem. 

Just as computer hardware manufacturers proceed at 
a fast clip to improve their products' performance and 
capabilities, so too will programmers expand their thinking 
to produce more efficient and creative languages. R-E 



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state instrument measures 3" x 6" x1Yi" 
and fits In a pocket. Yet it contains 
sophisticated electronic circuitry, a 
microphone, and three red diodes. It 
analyzes the human voice for stress. 

Once you learn, in about 30 minutes, 
how to use the Hieronymus Machine, you 
will be able to discover whether a person 
is calm or stressful — merely by monitor- 
ing his or her voice. 

DEFINITELY NOT A "LIE DETECTOR" 

The Hieronymus Machine is not a He 
detector. Nor is It a "truth" device. Even 
the famed polygraph machine Is not a 
lie detector, plain and simple. The 
polygraph can be used to monitor a per- 
son's pulse, respiration, blood pressure, 
and galvanic skin response, bodily func- 
tions affected by stress. 

And in the hands of a skilled operator, 
the polygraph can be used to gain In- 
sights about a person's stress levels when 
talking about certain topics. But a very 
real part of the polygraphs usefulness Is 
the "Hieronymus Effect," which we'll get 
to In a moment. 

SPIES AND COUNTERSPIES 

During wartime, counterintelligence 
experts wondered If science could come 
up with something simpler than the 
polygraph to help ferret out spies. 
Researchers became attracted to the 
theory that human voices emit "micro- 
tremors," low-frequency vibrations that 
are generally Inaudible or masked by 
other voice components. 

An article In Popular Electronlci (April 
1980) describes the theory In detail. But 
the short story Is that after spending 
millions of dollars, researchers 
developed a voice stress analyzer. Now, 
the authors of the definitive article In 
Popular Electronic* have perfected a 
personal voice stress analyzer, which we 
call the Hieronymus Machine, 

WHAT IT DOES, HOW YOU USE IT 

The Hieronymus Machine electronically 
measures changes In voice micro- 
tremors. The read-out Is simple; one red 
diode Indicates normal, two show 
moderate stress, and three reveal 
greater stress, ranging from mild to 
severe anxiety. 

You, as the operator, could use the 
Hieronymus Machine like a thermometer, 
checking the "fever level" of stress. As 
you gain skill, your Judgment will Im- 



prove, enabling you to pursue or avoid a 
line of questioning or discussion that pro- 
duces stressful responses. 

MANY USES AT HOME OR WORK 

You can use the Hieronymus Machine 
at home to have fun with your family. 
You'll discover how It responds to dif- 
ferent people's voices, what effect 
laughter and singing have on It, and 
even evaluate pollticans' speeches over 
TV or radio. It works quite well on transmit- 
ted voices, as well as over the telephone 
or with tape recordings. 

Next, try It on friends. See how well so- 
meone's favorite fish story holds up when 
you point out that the Hieronymus 
Machine doesn't believe a word of it. 
And watch that poker face disappear as 
the "stress" diode steadily Insists you're 
not getting the whole story. 

BIOFEEDBACK FOR YOU 

if you're required to talk In front of 
groups or need to speak convincingly to 
one person at a time, you can use the 
Hieronymus Machine to monitor your 
voice and learn a more relaxed, self- 
assured, persuasive style of delivery. If 
you wanted to learn hypnotism, a relax- 
ed voice would be a real asset — and 
the Hieronymus Machine could help you 
achieve It, 

At work, there are numerous situations 
In which the Hieronymus Machine could 
work wonders. Here's how: Hieronymus 
Bosch was a 15th-century painter known 
for his startling originality. He was also 
something of a medical practitioner, 
and he believed that patients could be 
cured by passing stones over their 
bodies. Bosch achieved success 
because his patients b*ll»v«d that a 
cure was taking place. 

Nearer our own time, a couple of 
science fiction writers concocted a 
devise they named after Bosch: it pro- 
duced varying sensations In the user 
depending on where a dial was set, from 
zero to 100. The amazing thing was that 
this machine worked on subjects even 
when It wasn't plugged In — a perfect 
Hieronymus Effectl 

Now we have a true Hieronymus 
Machine, the Voice Stress Analyzer, it ac- 
tually works, and among other things of a 
scientifically verifiable nature, It pro- 
duces the Hieronymus Effect. In Its 
presence, people suddenly become 
more forthright. In some cases, with such 
a machine present, employees being 

CIRCLE 38 ON FREE INFORMATION CARD 




asked about office theft became very 
cooperative In answering questions 
truthfully. Naturally, you'll want to use the 
Hieronymus Machine In plain sight and 
tell people what It does. This actually 
gets more cooperation from them. 

30-DAY TRIAL, 
MONEY-BACK GUARANTEE 

The potential uses of the Hieronymus 
Machine are limited only by your Im- 
agination. Try It at no risk for 30 days. 
We'll send you one or more with com- 
plete Instructions (9v. battery not Includ- 
ed). You'll be able to try it, experiment, 
even conduct your own "Investigation." 

Governments and police departments 
and huge corporations are already us- 
ing large (briefcase-sized) versions of this 
kind of machine, and they have to pay 
$3,000 or so for theirs. But you can have a 
personal Hieronymus Machine for only 
$119.95. If you're not satisfied, send it 
back (Insured) for a full refund, no ques- 
tions asked. If you want two, the cost Is 
$109.95 each. And If you want three or 
more for business use, It's only $99.95 
each. You're also protected by a 1-year 
parts and labor warranty. 

EXCLUSIVE BY MAIL FROM MERCURY 

The Hieronymus Machine cannot be 
obtained in stores or from any other 
source. To order, send check or money 
order to the address below. Or charge it 
on American Express, Carte Blanche, 
Diners Club, Master Charge or Visa. You 
can also call us toll free: 

800-526-2801 

or 
800-257-7850 

In New Jersey, call toll free 800-322-8650. 
Include $2.50 Insured shipping charge 
per Machine. N.J. residents please add 
5% sales tax. 
Or mall your order to: 



MM NATIONAL SALES GROUP 

ml niETCiRv 

W THE IMAGINATION PEOPLE'" 



Dept. RE 10. Lakewood Plaza 
Lakewood. N.J. 08701 



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5229 South Highway 37 • P.O. Box 2003 • Bloomington, Indiana 47402 • 612/ 824-2424 



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This synthesized pulse generator has a range of from 1/100 Hz to 1.000 MHz. 
Use it for working with logic circuits — or with analog devices well into the HF range. 



GARY McCLELLAN 



ONE OF THE HANDIEST PIECES OF ELEC- 

tronic equipment you can have is a good 
signal generator. But one particular 
area that has been neglected is pulse 
generators for driving logic circuitry. 

The Program ma 1 will change that. 
Now you can build and test digital cir- 
cuits without expensive clock circuitry, 
pulse generators, or other sources. The 
Programma 1 marries the frequency 
stability of a synthesizer with a logic- 
level output. And, when you are not 
using it to run your breadboard logic- 
circuits, you can use it as a regular 
signal generator. 

This design has many exciting fea- 
tures. The output frequency is pro- 
grammed via four BCD (Binary Coded 
ZJecimal) front -panel switches. There 
are a total of 9990 possible frequency 
combinations available, with each one 
offering crystal-controlled accuracy. 
Also included in the Programma 1 is a 
multi-stage frequency divider that ex- 
tends the frequency range even farther! 
In fact, you can readily generate signals 
from 0,01 Hz to 1.0000 MHz. The 
accuracy of any of these frequencies is 
within ± 0.005%, if the generator is ac- 
curately calibrated. As far as the output 
voltages are concerned, you have your 
choice of standard TTL/CMOS output, 
or an adjustable to 5-volt output. This 
is ideal for general purposes like running 
logic circuits, or for use as an audio 
signal generator. And, since its fre- 
quency range extends into the RF 
spectrum, the Programma 1 is also use- 



ful for AM radio alignment. Still other 
features include drive capability for one 
TTL load, and an error lamp that tells 
you that the frequency selected is cor- 
rect. This lamp is helpful as a diagnostic 
device, should troubleshooting become 
necessary. 

There's more 

Not to be overlooked is the design of 
this instrument. Thanks to the latest 
CMOS circuitry, it uses just ten IC's. 
Contrast that number with the seventeen 
IC's that are normally required in a 
comparable TTL system. Besides a re- 
duced IC count, you get CMOS ad- 
vantages like low power consumption, 
absence of drift-causing heat, and a less 
noisy signal. Also, the construction has 
been simplified to one small, single- 
sided PC board, that you can easily 
make or buy. Not to be neglected, the 
other parts have been kept to a minimum 
by careful engineering, to make buying 
them easier. In fact, great care has been 
taken to insure that all parts for this 
project are readily available. You can 
expect to be able to assemble the Pro- 
gramma 1 in just a few evenings, thanks 
to its simplified circuitry and good 
parts-availability. 

For the future 

With "smart" test equipment on the 
horizon, or instruments that interface 
with computers, this project will become 
more useful. By replacing the program- 
ming switches with appropriate IC buf- 



fers, the Programma 1 may be controlled 
by a microprocessor, automatically gen- 
erating the frequencies required. This 
technique is being used in industry for 
testing, and even alignment, of finished 
equipment. It's a big money saver, and 
you'll be hearing a lot more about auto- 
matic testing. The Programma 1 has 
this automatic test-capability built in 
right now, ready for the future — some- 
day you'll appreciate that! 

Theory of operation 

Figure 1 shows a block diagram of the 
pulse generator, so refer to it for details 
as you read the circuit description. 
Although the diagram has been stripped 
down to just the basics, the actual cir- 
cuitry isn't much more complex. In fact, 
you are going to read about one of the 
simplest frequency synthesizers ever 
designed. 

Why a synthesizer? 

You may be wondering why a synthe- 
sizer has been used in this project, and 
even, for that matter, what it is. Basi- 
cally, a frequency synthesizer is a cir- 
cuit that takes a single frequency from a 
quartz crystal, and uses it to generate 
many others, each with the accuracy 
and stability of the crystal. In the Pro- 
gramma I , a single color-TV crystal is o 
used to generate 9990 different fre- ^ 
quencies. In other words, you replace B> 
9990 crystals with one single -crystal jj 
frequency synthesizer. (Now you know £ 
why they are found in CB radios, and § 

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Fie. 1— BASIC FREQUENCY SYNTHESIZER, showing the four major sections. All this Is accomplished 
by only three IC's! 



other places where lots of crystals once 
were used.) Through frequency synthe- 
sis you gain accuracy and save money. 
As you can see from Fig. I , the syn- 
thesizer consists of four basic parts. 
The first is the VCO (Voltage Controlled 
Oscillator. It simply generates a signal 
whose frequency can be varied by 
changing a DC control voltage. In this 
project, the VCO frequency can be 
swept from I kHz to I MHz. 

The next section is the reference 
oscillator. It provides a stable, fixed 
reference-frequency. In the Programma 
I , a single IC, combined with a 3.579545- 
MHz color-TV crystal, does the job. 
Next, a programmable divider takes 
over, dividing the VCO frequency. The 
exact divisor is selected by the front- 
pane! switches. In this design, another 
IC performs the entire task, and can 
divide the VCO signal by up to 10,000. 
The final section is the phase detec- 
tor. It compares the signal from the 
reference oscillator with the signal from 
the programmable divider. In operation, 
the phase detector outputs a DC voltage 
comparable to the difference of the two 
signals. The greater the difference, the 
greater the IX output is. On the other 
hand, if the two input signals are the 
same frequency, the DC output doesn't 
change. Since the DC voltage drives the 
VCO, it can now adjust the frequency 
until the signals on the phase detector 
input are the same. The result is a VCO 
output-frequency equal to the product 
of the divisor of the programmable 
divider and the reference oscillator fre- 
quency. In this project, the VCO and 
phase detector sections are all included 
inside one easy-to-obtain IC. That 
takes care of the basics. 

Refer to the schematic diagram in 
Fig. 2 for the circuit details. The pro- 
grammable divider is IC I , whose divisor 
is selected by the front panel switches. 
It is a single LSI IC. and it costs less, 
works better, and is easier to use than 
any other divider scheme. A unique 
feature of this circuit is that setting the 
switches to 0000 results in a divisor of 
10,000. That saves the cost of an extra 
switch. The phase detector and the 
VCO are in IC2. The divider input of 
the phase detector is pin 3, and the 



reference oscillator input is pin 14. The 
output is pin 13. It drives resistors R19 
and R20, and capacitor C6, forming a 
network known as a loop filter. Basi- 
cally, this filter does nothing more than 
clean up the VCO control voltage. 
Other phase-detector circuitry includes 
transistor Ql, which connects a LED 
to the error-detecting circuitry in IC2. 
If something goes wrong with the cir- 
cuitry, and the frequency is off, the 
LED will light. 

The VCO portion of IC2 is simple 
and straightforward. The DC control 
voltage is applied to pin 9. Resistor R 17 
and capacitor CI set the maximum 
operating frequency of the VCO. The 
square wave output signal appears on 
pin 4, ready for use elsewhere. The 
reference oscillator circuit consists of 
IC3, and it contains all the devices re- 
quired to excite TV crystal XTAL1 and 
to produce a 100-Hz reference signal. 
The balance of the circuitry on this 
board consists of five decade- dividers, 
IC4 — IC8, that simply divide down the 
output signal, giving a symmetrical 
waveform. Since the outputs of these 
IC's are all at CMOS levels, with a 10- 
volt swing, buffer IC9 has been included 
to convert the voltages to TTL-com- 
patable values. 

The power requirements of this cir- 
cuit are provided by IC10 and Zener 
diode Dl. These components provide a 
well-regulated 10 volts for the synthe- 
sizer, and 5 volts for IC9, which is used 
to drive 5- volt TTL devices. Power to 
the PC board is supplied by a 14-volt 
surplus battery charger. Not much cur- 
rent is required (about !0 mA IX), so 
the entire unit can be battery-powered 
if desired. 

Construction 

Now that you know how the Pro- 
gramma 1 works, let's put one together. 
One important reminder is in order if 
you are considering breadboarding the 
project — the output signal will be noisy 
unless you are careful. Like most other 
frequency synthesizers, this one has a 
high loop-sensitivity, and is suceptible 
to noise pickup. So if you wish to get a 
high-quality signal from this project, be 
sure to use a PC board. If desired, you 



can buy one, together with assembly in- 
structions and troubleshooting hints, 
from the supplier indicated in the parts 
list. Or you can "roll your own" using 
Fig. 3. 

Another important reminder concerns 
the quality of the parts you use. It 
shouldn't be necessary to remind you 
to use top-quality components, but if 
the urge to use cheap substitutes is 
overpowering, you may wind up with 
problems. Generally, the quality of the 
output signal will suffer, and frequent 
servicing may be required. Play it safe, 
and save time and money in the long 



PARTS LIST 

All resistors % watt, 5% unless otherwise 
noted. 

R1-R16, R19— 100,000 ohms 

R17, R18— 10,000 ohms 

R20, R22, R23— 2,200 ohms 

R21— 22 megohms 

R24-^t7 ohms 

R25 — 10,000 ohms linear taper pot (car- 
bon) with SPST switch 

Capacitors 

C1— 47 pF mica 

C2, C6- 0.1 ^Fdisc 

C3, C9— 33 pF mica 

C4 — 10 pF mica 

C5 — 6 to 20 pF trimmer (E.F. Johnson 
275-0320-005 or equivalent) 

C6 — 4.7 a*F, 16 volts, tantalum 

C7, C10— 10 #F, 16 volts, tantalum 

C11— 220 #F, 25 volts, electrolytic 

Semiconductors 

D1— 5.1 -volt, 1-watt Zener diode (1N4733 
or equivalent) 

D2. D3— 1N4148or 1N914 

Ql— 2N3906 

IC1— CD4059AE CMOS divider (RCA) 

IC2— CD4046 CMOS PLL (RCA) 

IC3— MM5369EST CMOS oscillator (Na- 
tional) 

IC4-!C8— MM74C90N CMOS counter (Na- 
tional) 

IC9— CD4050 CMOS hex buffer iRCA) 

IC10— MC78L05 5-volt regulator (Motorola) 

LED1— .200-inch discrete LED 

S1-S4 — BCD thumbwheel or lever-type 
switches (C&K 332110000, EECO 1800 
Series, or equivalent) 

S5 — 6-position, single-pole rotary switch 

S6— SPST switch (mounted on R25) 

XTAL1— color-TV crystal, 3.579545 MHz, 
32 pF parallel-resonant, HC-33 case 

J 1— jack to match connector from power 
source used 

J2— RCA-type jack 

J3 — BNC connector 

Miscellaneous: PC board, 14-volt DC 
power supply or battery eliminator, one 
8-pin IC socket, five 14-pin IC sockets, 
two 16-pin IC sockets, one 24-ptn IC 
socket, enclosure, knobs, solder, rib- 
bon cable, etc. 

PC boards are available. Order part 
SCG-1. Price, postpaid In USA, $10.00; 
California residents add 6% tax. Foreign 
orders please add $3.00 tor shipping and 
handling. Order from: Technico Services, 
Box 20HC Orangehurst, Fullerton, CA 
92633. 



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FIG. 2— PROGRAMMA 1 has a frequency range of from 0,01 Hi to 1.000 MHz. BCD panel-mount 
switches are used for exact selection of pulse frequency. 




\* 4-3/8 INCHES 

FIG. 3— FOIL PATTERN for the Programme 1. See parts list for supplier If you prefer not to make your 
own PC board. 



run by using top-quality parts. This is 
especially important with respect to the 
IC's and the capacitors. Although the 
need for quality IC's is obvious, the 
capacitors should be the type (e.g. mica 



or tantalum) and value specified. This 
will insure the best possible signal 
stability and purity at a small additional 
cost. 

Refer to Fig 4 as you install the parts 



on the PC board. A good place to start 
is with the IC sockets. Begin by install- 
ing a 24-pin socket at ICl , then an 8-pin 
unit at IC3. Check to be sure al! pins are 
soldered in place on the sockets — 



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be shown differently from manufacturer to manufacturer. Orientation given here Is correct for all 
versions. 



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especially on the 24-pin one. Continue 
by installing 16-pin sockets at IC2 and 
IC9 locations. Finish up the socket in- 
stallation by adding 14-pin sockets to 
IC4 — IC8 locations. This board has one 
jumper wire, which you can insert next. 
Locate it in Ftg. 3 first (between IC4 
and CI 1), then install it on the board. A 
piece of bare wire cut from a resistor 
will work fine. 

Now you are ready for the resistors. 
Start with the 100K units, placing 16 of 
them around IC1 (R1-RJ6). After that, 
install R21, 22 megohms, next to the 
IC3 socket. Then mount a 10K resistor 
on either side of IC2. Note that, while 
the leads of R 17 are simply bent and in- 
serted in the board, Rl8*s leads must be 
left longer (about !4-inch) to cover the 
distance between the holes. Next, in- 
stall 2.2K resistors at R20 and R22, and 
a 100K resistor at R19. Move over to 
the other edge of the board and mount a 
47-ohm resistor at R24. And finish up 
with R23, 2.2K. Be careful not to con- 
fuse the location with that for D3> just 
below it! 

The diodes are next, and the installa- 
tion will go quickly. Be careful to install 
them correctly, and double-check 
against Fig. 3 afterwards. Start with DI, 
a 1N4733 5.1-volt Zener diode, and 
then install 1N4148 diodes at D2 and 
D3. That's it. 

The next step is to install the capaci- 
tors. You can start with C7, 10 uF. 
Orient it as shown in Fig. 3. Then in- 
stall a 33 pF mica capacitor at C3 , and a 
10 pF mica capacitor at C4. The trimmer 
is next, so examine C5 and note that the 
ground terminal is probably marked in 
some way. If there's no arrow or paint 
dot, then trace out the pin that attaches 
to the adjustment screw. Install it so 
the ground terminal faces the edge of 
the board. If the trimmer is reversed, 
the project will work, but will be tough 
to calibrate due tc capacitance added 



by your hand on the screwdriver! Con- 
tinue with C6, a 4.7 jtF tantalum, and 
just above it install a 47 pF mica at CI. 
Move up the board and install a 0. 1 fiF 
disc at C2, and another at C8, at the 
left. Then install a 33 pF mica at C9. 
Mount another 10 ^F tantalum at C10, 
below IC9. Finish up the capacitors 
with a 220 ixF electrolytic at CI i. Stop 
for a moment, and check your capacitor 
installation. Correct any mistakes you 
may find and then continue with the 
construction. 

By now your circuit board will be 
nearly complete and will look like the 
one in Fig. 5. There are just a few parts 
to go, so let's finish up the board. 
Mount crystal XTAL1 first, pressing 
the case down firmly against the board 
before soldering the leads. Then install 
1C10, a 78L05 regulator next to Cll. 
(Note: The 78L05 pinout given by some 
manufacturers may differ from that 
shown here. To the best of our knowl- 
edge, our pinout holds true for all ver- 
sions of the 78L05- Editor). 

Finish up with the IC's, starting with 
IC1 . Note that the foil side of the board 
and Fig. 4 indicate the orientation of 
each IC. Use them to guide you. After 
the IC's are installed, check the board 




FIG. 5— FRONT-PANEL SWITCHES are con- 
nected to PC board by ribbon cable. Note power 
jack, J1, at back of enclosure (upper left). 



over very carefully for errors. Then set 
the board aside for a while. 



Preparing the case 

Although the original version of this 
project was built in an old meter case, 
you are welcome to use any suitable en- 
closure. It should be metal, though, to 
prevent radiation of stray signals that 
can interfere with your tests. As far as 
the layout is concerned, you can ex- 
ercise your judgment in the matter, or 
duplicate the box layout shown in the 
photos. Here are a few helpful tips if 
you decide to "roll your own:" First, 
be sure to locate the error LED and 
FREQUENCY switches close together. 
This is important because they are used 
together. Also, the output jacks and 
level pot should be located close to- 
gether. In fact, they should be positioned 
closer to one another than they are on 
the prototype (see Fig. 7), since long 
leads degrade the shape of the signal at 
high frequencies. All signal -carrying 
leads, for that matter should be kept as 
short as possible. The rest of this part is 
straightforward. 

Final assembly 

After you have the enclosure pre- 
pared, you're almost done. Probably 
the best place to start is to wire the 
board to the frequency switches, 
Refer to Fig. 2 (schematic) and Fig. 6 
for details. 

Start by wiring all the common pins 
of the switches together with a piece of 
bus wire. Then attach a short piece of 
stranded wire to it. This is the "COM" 
lead to the circuit board. Next, you can 
wire the switches themselves, starting 
with S 1 . Note that S 1 is the MSD (Most 
Significant Digit), and that it is the 
switch section on the far left of the 
panel as you view it from the front Use 
short pieces of four-conductor ribbon 
cable for the connections. You can 
attach the ends of the switches first. In 
fact, it might be a good idea to solder a 
length of cable to each switch first, and 
then to the circuit board later. This is 
easier 1 if you have mounted the switches 
in the box already. 

After the wires are attached to the 
switches, connect the cable from SI to 
the holes on the board. Note that some 
BCD switches are coded "1 2 4 8" and 
that corresponds with the "A B C D" 
marked on the board. In the same man- 
ner, wire the remaining switches. 
Switch S4 will be the section on the 
right when viewed from the front. 
Finally, connect the "COM" wire, and 
you are through with SI — S4. 

Now for switch S5. Prepare a short 
length of six-conductor ribbon cable 
and connect one end to the fixed con- 
tacts of S5. Then attach a single piece 
of wire to the wiper terminal. Connect 
the other ends of the ribbon-cable wires 



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FIG, 6— CONNECTION OF OFF-THE-BOARD components. Resistor R25 Is a part of the on /off switch, 
S6, All leads should be kept as short as possible to avoid difficulties at high frequencies. 

reasonably well without any calibra- 
tion, you might want to make a simple 
adjustment for the best frequency ac- 
curacy. To do this you'll need an ac- 
curate frequency counter and an xlO 
oscilloscope probe. Supply 14 volts DC 
to J 1 , then rotate the level pot to turn 
on the power. At this point there's no 
need to set any of the switches on the 
project. Connect the probe to the count- 
er, and clip its ground lead to the pulse 
generator. Then, carefully touch the 
probe to pin 7 of the MM5369EST(IC3). 
You should get a reading of 3, 579,5 x x 
(-= variable) Hz. Adjust the trimmer so 
that you get exactly 3,579,545 Hz and 
you are all set. Disconnect the counter 
and you can close up the box. 

Operation 

Operating the Programma 1 is a snap! 
Simply set the frequency you want on 
the thumbwheel switches, and watch 
the ERROR LED. It will blink about four 
or five times, then go out. When it does, 
you are locked on frequency. Switch S5 
selects the frequency you get out. For 
example, on the i mhz range, you'll get 
an output from about 900 Hz to exactly 

1.000 MHz. Switch to the lOO-kHz range 
and you'll get a tenth of that or 90 Hz to 

100 kHz. The rest of the ranges work 



FIG. 7— THIS LAYOUT works well, but Is not 
Ideal. Output jacks and "level" pot should be 
located closer to one another to keep leads 
short 

to the ' L E" through "J" outputs, and 
the single wire from the wiper to "IN," 
This wiring is shown in more detail in 
Fig. 6. Next, the LED may be installed. 
Finally, wire up pot R25, the output 
connectors, and the power leads. Don't 
forget to run a short wire from the cir- 
cuit-board ground foil to the box. A 
good place for this is at the "minus" 
terminal of Cll (220 uF). Wire up the 
power jack, J 1 (on the back of the box) 
and you are finished. 

Calibration 

Although this project should work 



in the same manner. If you would like 
an adjustable output instead of the 
TTL-level signal from J3, simply use J2, 
and adjust the level control for the 
voltage you want. There's nothing to 
using this project! 

Here are a few tips to help you get 
the most out of your project. First, due 
to the design of VCO and divider cir- 
cuits, switch positions from 0001 
through 0009 will be inoperative. The 
ERROR light will come on as a reminder 
that these numbers are invalid. Note 
that the setting of 0000 is OK; in fact it 
will give you 1. 000 MHz, but watch 
those other settings. As far as the out- 
put signal is concerned, it is a constant- 
amplitude squarewave with a 50% duty 
cycle. However, if you start to load it 
down, the amplitude will change. Also, 
the waveform quality will tend to 
deteriorate as the frequency goes up. 
So, for best results when you are in- 
terested in waveform quality, use a 
very light load, and watch out for the 
effects of coaxial cables at the higher 
frequencies. Finally, some degradation 
of the squarewave will be noted at the 
adjustable output (11) at high fre- 
quencies. This is normal where a simple 
pot-attenuator is used. 

Some uses for the Programma 1 

There are a great many uses for this 
pulse generator. Although it was de- 
signed for operating digital circuits, it 
does well in other areas, too. Here are a 
few things that can be done with it: 
checking TTL divider circuits, decimal- 
counting uses (why not make a timer?), 
general logic -troubleshooting, and 
much more. 

In the analog area, it can be used for 
amplifier squarewave -testing, electronic 
music (it generates a wild glide tone!), 
AM radio alignment, and more. How 
about using it as a short-wave radio 
marker-generator? (The harmonics go 
well into the HF spectrum.) Or as a 
programmable sinewave generator? 
(Active filtering can change the square- 
wave to a sinewave.) There are 
numerous uses for the Programma l. 
How many can you think up? R-E 



Television viewers want 
low power consumption 

More than six out of ten TV viewers believed 
that reduced power consumption would be 
a "very useful feature" In a recent nation-wide 
survey carried out by Venture Development 
Corp.. a Wellesley. MA. market- research firm. 
Prospective buyers would be willing to pay up 
to $41 additional for significant energy-saving 
features. Runner-up. with just about 60 percent 
of the surveyees, is better sound quality, and 
TV listeners feel that better speakers would 
justify a $66 increase on the price of their sets. 
Stereo sound, however, would be worth $80. 
About 40 percent of the viewers felt that auto- 
matic tuning through the use of vertical interval 



reference would be "very useful," and 25 per- 
cent opted for pushbutton channel selections. 
(In view of the low power consumption of 
modern TV sets, it might be interesting to in- 
vestigate how much of the response to that 
question is due to consumer ignorance and the 
present campaigns for energy economy! 

Special features mark 
new video disc player 

The SetociaVision video disc player, a prod- 
uct of RCA, will come with two features in its 
latest design that can greatly increase its use- 
fulness to the home viewer. 

Visual Search allows the viewer to scan the 
program at many times normal speed — either 



forward or backward — while continuously dis- 
playing a picture on the TV screen. Rapid 
Access locates— at high speed— any desired 
segment on the disc. It uses a digital time indi- 
cator. (RCA had previously demonstrated a 
mechanical time indicator,) 

The first VideoDisc players will be mono- 
phonic, since the users will be owners of 
present-day TV receivers, all of which are 
mono. Stereo versions will come later. 

RCA expects to have the first players on the 
market in the first quarter of 1981. The agree- 
ments that have been reached with CBS and 
Zenith are expected to result in those two firms 
entering the video disc business with products 
based on the RCA capacitance system. 



O 
O 



CO 

o 



91 




D 




Ui\iicopi\l -1 

POBOJ 

Assembling the Legs 

Part 3 — Every robot should have a way to get from place 

to place. This part of the Unicorn-One series describes the 

mobility base, which allows the robot to do just that. 

JAMES A. GUPTON, JR. 




HAVING ALREADY OUTLINED THE CON- 

struction of the robot's arms and hands in 
parts 1 and 2 of this series, we'll now 
discuss its mobility base — the powered 
section that allows it to move from place 
to place. 

The mobility base houses the robot's 
electrical power source, its drive motors, 
and the heart of its wiring system. 

While it may be necessary to purchase 
some of the components of the mobility 
base new, there is still a lot of money that 
can be saved through judicious scroung- 
ing. Remember — it doesn't really matter 
what you use to get something done, as 
long as it does get done and the results 
are what you need. 

We'll present two approaches to con- 
structing the mechanism of the mobility 
base. The first, which may require some 
cash outlay, is the one we've found to give 
the best results. The second, which is 
more economical, is a bit trickier and not 
quite as acceptable to the purist. Still, 
both work. 

Figure 19 illustrates the dimensions 
and external appearance of Unicorn- 
One's mobility base. Actually, for the 
sake of economy, the original housing was 
made using a large discarded electronic 
chassis, as seen in Fig. 20. 

One of the most stylish ways to go is to 
use Bud aluminum or steel panels, plates 
and frame sections, which can be ordered 
through most electronics parts distribu- 
tors. The parts list shows the designations 
of the Bud parts required. Unfortunately, 
this approach, which requires only a little 



cutting and drilling, can turn out to be 
fairly costly. 

You might, therefore, want to turn to 
scrounging (a local sheet metal firm 
might have some odds and ends that 
could be picked up cheaply), or purchas- 
ing material that was not precut. Be sure, 
though, that the aluminum (if that's what 
you're using) is type 5005 — an indication 
of its strength. You must bear in mind 
the fact that the mobility base will be 
supporting at least 30 pounds of the 
robot's weight and that if it is too weak, 
the mechanical integrity of the robot will 
suffer. 

Every part of the mobility base skin 
can be made from aluminum, except for 
the top. That should be fabricated from 
0.125-inch steel, both to support the 
weight of the body and to allow the bear- 
ings upon which the body will rotate to 
turn freely. 

The side panels can be made from 
.0625-inch aluminum, since they will not 
be responsible for bearing weight. An 
option is given in the parts list to use four 
19 X 7-inch side panels. These are not, of 
course, the dimensions shown in Fig. 19, 
but reflect the possibility of your choos- 
ing to build a square base, and also the 
use of a smaller size battery. Actually, the 
dimensions are not critical. Just make 
sure that the robot's center of gravity falls 
within the support points (the wheels) 
and that there is enough room inside the 
mobility base for the battery, motors and 
terminal strip. Be sure to allow sufficient 
clearance for you to access the battery. 



Finally, aluminum angle-bracket, 
available at hardware or building-supply 
stores, will do very nicely for the frame in 
place of more expensive materials. 

Access to the mobility base is provided 
by a hinged plate at the back (Fig. 21). 
Lay out the interior so that the important 
parts can be reached through the opening 
this plate provides. Use the diagrams and 
photographs in this installment to guide 
your thinking. There is nothing forcing 
you to make a carbon copy of the original 
Unicorn-One. Use your imagination and 
ingenuity. 

A 2'/:-inch wide curved opening will 
have to be cut in the top of the mobility 
base (refer to Fig. 19) to permit wires to 
be routed between the base and the body. 
This opening may be located at either the 
front or the rear of the top section. You 
should make sure that the wires will not 
jam in the slot as the body rotates — don't 
forget to allow slack in the wires for this 
purpose — and the slot should be edged 
with some soft material such as several 
layers of electrical tape, or flexible tubing 
which has been slit to fit over the cut 
metal, to prevent chafing of the wires' 
insulation. 

Transmission and drive train 

There are three main sections to the 
"mobility" part of the mobility base. 
They are the motors, the wheels, and the 
parts which transmit the action of the 
former to the latter. The wheels are easy 
to obtain. The two 6-inch driven wheels 
can come from an abandoned child's wag- 



92 








/ ■ x ■ 


r—i 




\ 


—J 


V ^^ 



FIG. 19— MOBILITY BASE layout and dimensions. Figures here are for author's prototype — yours may 
differ (see text). Top plate is made ot steel; rest can be aluminum. 




FIG. 20— EARLY VERSION of the mobility base 
enclosure, built from parts at hand. 




FIG. 21— HINGED BACK PANEL allows access 
to components mounted inside mobility base. 

on or scooter, or from a lawn mower ser- 
vice shop, to name a few sources. The 
front caster wheel is probably best found 
in a hardware store. 
The preferred motors, used in the first 



approach, are gear motors which run at a 
speed of between 20 and 25 RPM. 
Sources for a 22 R PM motor are given in 
the parts list. If you elect to go the second 
route, you can use simpler, higher-speed 
motors. Again, refer to the parts list. 

Figure 22 illustrates a section of a 
mobility base constructed using the 22 
RPM gear motors. The motor is very eas- 
ily attached to the frame of the base 
through the use of an aluminum angle 
bracket at the bottom and two Winch 
OD spacers at the top. Attachment is 
made using the existing motor mounting- 
holes. By using counter-sunk flat-head 
machine screws, the exterior of the mo- 
bility base is left free of protrusions and 
can be painted without further 'finishing. 

The wheels, which usually come with 
Winch shafts, are coupled to the Winch 
motor shaft by means of a 2.5-inch long, 
Winch spacer, with an inside diameter of 
Winch, secured to both the axle and the 
shaft by means of set screws. Alterna- 
tively, a . 374-inch OD coupler may be 
used and the shaft and axle secured to it 
with dowel pins. Refer to Fig. 23 for 
details. 

Two motor/wheel assemblies are used, 
one on each side. Front support is given 
by a castered wheel located at the front of 
the assembly. Steering is accomplished 
by driving only one motor, using the otli- 




FIG. 22— ONE OF THE TWO gear motors used to 
drive the mobility base's wheels. 

er as a pivot about which the robot turns. 
Or, for speed, one wheel may be run in 
one direction while the other is run in the 
other. 

The alternate method for driving the 
mobility base, illustrated in Fig. 24, uses 
less expensive, but much faster-turning 
electric motors coupled to the wheels 
through a set of worm gears. This meth- 
od, while less expensive in terms of mate- 
rials, requires a lot of painstaking labor 
and probably the use of a well-equipped 
machine shop. It is presented here mostly 
as an exercise in developing alternate 
ways to achieve the same results. 

The motor is mounted on a Winch 
thick aluminum plate which, in turn, is 
mounted on the inside of the bottom of 
the mobility base using four spacers. The 
shaft of the motor protrudes down 



O 

o 
ro 
m 

to 

00 

o 
93 



i 




NOTE: 

DRILL LAYOUT FOR MOUNTING GEARMOTQR 
BASED ON .125 MOBILITY BASE SIDE THICKNESS 



-3.25- 



HEIGHT WILL VARY 
WITH WHEEL SIZE 

— * 



USENQ. 19 DRILL 

(0.166) A m 

COUNTERSINK FOR 9M 
FLAT HEAD SCREW 



-2.50- 



,75 



ID TO CLEAR 
AXLE COUPLER 



m. 



2.38 



©! 



USENO.36DRILLT0TAP 
6-3ZORDRILLTHRDUGH 
COUPLER AND .2487 SHAFT 
WITH .9625 DRILL FOR 
DOWELPIN 



2.58 



T 



~l If* 




.30 



WHEELAXLE COUPLER 



.50 FORSET SCREW 
.375 FOR LOCK PIN 



?b 



-2.50- 



.25 



*.25p — 

25 "• — 



<fr- 






3=C 



IE 



2.00 

(TAP B-32) 

3.00 



.50 
J_ 



ALL DIMENSIONS IN INCHES 



ALUMINUM ANGLE 
MOTOR SUPPORT 



FIG. 23 — MECHANICAL DETAILS of 22-RPM gear-motor mounting. Some dimensions may change if 
sizes of wheel or wheel-shaft you use differ from those used by author. 



O 

Z 

o 

IE 
F- 

o 

UJ 
_1 

ai 
O 
Q 
< 
rr 









PARTS LIST 










Supplier's 






Supplier's 




Item 


Size 


Quantity 


part no. 


Supplier Item 


Size 


Quantity 


part no. 


Supplier 


Sheet metal 


.125 x 10.5 x 19 


2 


PA-1106 


®,© 


or 








{type 5005) 

aluminum 


inches 
.125 x 10.5 x 


2 


(5005 alum.) 
PA-1106 


®.® 


3-amp split- 
phase 


2 


61.085 


© 




15.75 inches 






Battery 


fead-acid, 12- 


1 


local 






.125 x 19.5 x 
15.75 inches 


1 


PS- 1258 
{steel) 


®,® 


volt, 12 am- 
pere-hours 




supplier 






.125x19x 
15.75 inches 


1 


PS-1109 
(alum.) 


®.© 


gelled-electro- 
lyte, for 12 
volts, 12 am- 


as 
required 


see back of 

Radio- 
Electronics 




(Optional— for 


.125 x 19 x 7 


4 


PA- 11 04 


®,<§> 


pere-hours 








use with mo- 


inches. Note: 




(alum.) 












tor-cycle bat- 


.0625 sheets 








SUPPLIERS: 


tery and 19- 


may be used 










inch square 


for sides if de- 








A, The Robot Mart 


base) 


sired. 








Room. 1113 
19 W. 34th St. 


Aluminum angle 


.0625 x Vi 


16 feet 


Local hard- 




New York, NY 10001 




inches 




ware supply 
store 




{$3.00 for catalog) 




or 








@ Wmired M. Berg, Inc. 


.125X.75 


.125 x .75 in. x 
3 feet 


1 


BI-2901-3 


©,© 


499 Ocean Avenue 

E. Rockaway, NY 11518 




. 125 x. 75 in, x 


1 


BI-2901 


®.@ 


© Edmund Scientific Co. 




12 feet 








101 East Gloucester Pike 
Barring ton, NJ 08007 


Rear panel 


1x12 inches 


1 


Local hard- 






hinge 






ware supply 
store 




[§) Gledhill Electronics 

P.O. Box 1644 


Worm gear 


24-pitch— V«- 
inch bore, 30 
teeth 


2 


W24b37-F30 


®.® 


Marysville, C A 95901 

,G.;> Bud Industries, inc. 

Parts may be ordered through 


Worm 


Double pitch 


2 


W24S-4D 


®.® 


local electronics supplier. 


Wheel motors 


22 RPM gear- 
motor 


2 


715-900153 
(Brevel) 


*&• ^ NOTE: Part numbers for all items with "G" shown as supplier are 
those used by Bud. 



94 








•* 5.00 H 






* 3.00 *] 




11 


° 1/4" ALUMINUM PLATE ° 


t 


Q 


TAP 4 /JSZX 

CORNER f /f_[\\ 


o 
in 

t 


C7 


HOLES I (i J ) 

8-32 v^i^ y 








/V^©^/ 






f 


o / o 






NOTE: 

BEARING MANSERS CUT 

FROM 750" ALUMINUM PLATE 

.375 ALUMINUM SPACER. 
LENGTH L VARIES WITH MOTOR- 
AND GEAR DRIVE USED. 



1.125 DIA. 
CUTOUT FOR 
MOTOR SHAFT 
AND WORM 

HOUSING SCREWS 
(2) ATTACH MOTOR 
TO MOUNTING 
PLATE a 



^ZZZ22ZZZZ^ 



IE 




MOTOR HOUSING 
SCREW 



fSf/S. 



H. 



.3748 OD/,250 ID COUPLER 



-2.50- 



-5.00- 



8 - 32 SOCKET HEAD SCREW ^ 

ADAPTER HALF INCH WHEEL AXLE 
TO .2497 SHAFT 



\ WORM GEAR 



WORM* 



PIN BOTH SHAFTS WITH 
.0625 DOWEL PINS 



-8.50- 



RED 

BLUE 

ORANGE 

GREEN 
WHITE 
BROWN 
YELLOW 
SLACK 




BROWN 

WHITE 

BLUE 

YELLOW 

GREEN 

ORANGE 

RED 

BUCK 



OO 



Q£. 



BLACK 
RED 

ORANGE-l 
GREEN / 
ORANGE\ 
GREEN / 
WHITE 
BROWN 



> 



YELLOW 

RED 

ORANGE 

GREEN 

WHITE 

BLUE 

YELLOW 

BLACK 



to i 



GREEN 

RED 

ORANGE 

GREEN 

BLACK 

ORANGE \ 

RED J 



} 

} 
> 



HORN GROUND 
+ 12 VDC 

LEFT WHEEL MOTOR 
LEFT ELBOW MOTOH 
LEFT SHOULDER MOTOR 



CASSETTE REMOTE CONTHOL 
RIGHT HAND SOLENOID 12 VDC 

ROBOT BODY ROTATION MOTOR 

GR0UNO 

LEFT HAND SOLENOID 12 VDC 
ROBOT LIGHTS 12 VDC 
LEFT ELBOW UP LIMITSWITCH 



LEFT ELBOW UP LIMITSWITCH 
LEFT ELBOW DOWN LIMITSWITCH 

RIGHT ELBOW UP LIMITSWITCH 

RIGHT ELBOW DOWN LIMITSWITCH 



BROWN 

WHITE 

GREEN 

ORANGE. 

GREEN \ 

ORANGE/ 

RED 



} 



RIGHT SHOULDER MOTOR 

RIGHTELBOW MOTOR 

RIGHT WHEELMOTOR 
+ 12VDC 



h 



■17.00" 



mn^^.l....!^*^...!..!.!! 



1 0.375X6.00" SPACER ROD 



NOTE: 



MOUNT 4 BARRIER STRIPS ON 
ALUM1NUMANGLE1"X1"X17" 



6.00 



ALL DIMENSIONS 
IN INCHES 



ALL DIMENSIONS IN INCHES 



FIG. 24— MORE COMPLEX DRIVE MECHANISM 
is shown above. Power is transmitted to wheels 
through right angles, by means of worms. Gear 
motor drive is simpler and more reliable. 

FIG. 26— THIRTY-TWO TERMINAL barrier strip 
(al left) for power distribution and control. Will 
first be connected by cable to control box and 
later directly to R/C receiver or computer. 

through the mounting plate and through 
a hole in the bottom plate of the mobility 
base. Attached to the end of the shaft is a 
double pitch worm. This worm meshes 
with a 24-pitch, 30-tooth, worm gear, 
affixed to the end of the shaft which con- 
nects to the wheel. As can be seen from 
the diagram, several bearings are needed 
for this method and the bearing hangers 
(the plates which hold the bearings and 
are attached to the frame of the body) 
must be very carefully machined if things 
are to work right. Also shown in this dia- 
gram is another coupler, used to extend 
the length of the wheel shaft. 

While this method can be made to 
work, it is one place where you might 
want to consider splurging and buying 
the gear motors to use in the first method 
presented. The extra cost will be more 
than offset by the ease of construction 
and the final result. 

Power sources 

Since Unicorn-One is a mobile robot, 
it's intended that he carry his own power 
source with him. He obviously can't run 
on flashlight batteries — in fact he needs 
ten to twelve amps at 1 2 volts. The most 
economical way of obtaining this power is 
through the use of a conventional lead- 
acid battery. 

A motorcycle battery, mounted as 
shown in Fig. 25, will do the job nicely. 
(Note the plate to the left of the battery, 
which brings its leads to the outside for 
recharging purposes.) A frame should be 
continued on page 1 26 



O 

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33 
to 

09 

o 
95 






Dot /Bar- Graph 
Display Drivers 

New IC's simplify the design of LED displays. 
They're capable of doing a lot more than that, too! 



THE USE OF MULTIPLE LED'S IN A BAR- 

graph fashion to display analog signals is 
becoming increasingly popular. The 
reasons include low cost, ruggedness, 
high visibility, ease of interpretation, 
fast response time, low voltage and cur- 
rent requirements, and long life. No 
other display technology combines all 
those advantages. For example, electro- 
mechanical meters can have better 
resolution, but they respond less quick- 
ly and are sensitive to shock and vibra- 
tion. Liquid-crystal displays draw less 
power but are slow, and difficult to read 
in dim light. Bar graph displays based on 
LED's are used in stereo amplifiers for 
power meters, in tuners for signal- 
strength indicators, and in cameras for 
light meters. In all of those examples, 
the display must be interpreted quickly 
and easily, but high resolution is not 
required. 

Recently, IC's have been introduced 
that considerably simplify the task of 
driving a LED array with analog signals. 
Examples of those include National 
Semiconductor's LM3914 and LM3915 
LED Dot/Bar Display Drivers. Those 
extremely versatile devices have a 
reference, a voltage divider, and ten 
comparators all on one chip. Besides the 
LED's, only a few resistors and a ca- 
pacitor are required to complete the dis- 
play circuit. Either a bar or dot display 
(only one LED on at a time) is possible. 
The on-chip voltage reference is fully 
regulated, remaining constant while the 
power supply feeding the IC can be any- 
where between 3 volts and 25 volts! 

How it works 

A block diagram of the LM3914 is 
shown in Fig. 1 where the IC is wired up 
as a simple 2.5 volt full-scale meter. The 
IC's internal reference forces the volt- 



MICHAEL X. MAIDA 

age drop across Rl to 1.25 volts, causing 
a current equal to 1.25V/R1 or 1,25 mA 
to flow thru Rl and R2. The small 75- 
microampere current from pin 8 can 
usually be neglected so that the voltage 
at pin 7 is approximately 1.25V x (I + 
R2/RI) or 2.5 volts. The display range is 
set by the voltages at pins 6 and 4, the 
top and bottom ends of the LM39l4's 
internal voltage divider. For the 0-to- 
2. 5- volt meter shown, pin 6 is wired to the 
2.5-volt reference while pin 4 is ground- 
ed. The reference load current (I R p F ) in 
this example is equal to the 1 ,25 mA 
flowing through Rl plus the 0.25 mA 




flowing through the 10K divider or 1.5 
milliamperes total. 

The signal to be displayed is applied 
to pin 5, where it is buffered by a high 
impedance follower and fed to the in- 
verting inputs of the ten comparators 
that drive the LED's. The comparators' 
non-inverting inputs are connected to 
the taps along the voltage divider. In the 
LM3914, those taps are ail equally 
spaced. Here, another comparator turns 
on for every 250-m V increase of the in- 
put voltage, lighting up another LED, 

Current drive to each LED illumi- 
nated is set at ten times the reference- 

THiSLOAD 

DETERMINES 

Bl / LEO 

W BRIGHTNESS 



REF 
ADJ 




REFERENCE 

VOLTAGE 

SOURCE 

1.25V 



LM3914 



IK IK 1K IK 1K IK IK IK IK 
'W*-fV*VtAV»^MVfW'fW»TW»TAA A> r'iVV 



WWVVVVVV! 



6_ 
Rhi 



:omJ: 



|C0Ml2_ _ jjJSINLiLt LbU 



CONTROLS TYPE OF 
DISPLAY, BAR OR 
SINGLE LED 




17 



IE 



IS 14 



®M%%®M®A®Jih 



13 



-tf 



10 



LED 
+V 



C1 
ltluF 



FIG. 1 — THE LM3914 consists primarily of a series of comparators and a voltage-divider network. The 
trip point of each successive comparator is set higher than the previous comparator by the voltage 
divider. As the input voltage applied to pin 5 increases, the comparators trip in sequence. The 
comparators, in turn, illuminate their respective LED's. 



96 





FIG. 2— EXPANDED-SCALE VOLTMETER tor monitoring the output voltage Ot a 5-volt toglc-powef 
supply. Each LED corresponds to a predetermined voltage, as shown In the chart. 

load current deep) or 15 mA in this ex- can be different from the IC's V + . 
ample. Generally, LED currents from 
10 to 20 m A produce adequate bright- 
ness. A pot in series with a resistor con- 
nected from pin 7 to ground makes a 
simple intensity control, since it varies 



I REF without affecting the reference volt- 
age. Trimming the reference output 
voltage can be accomplished by varying 
R2. 

For a DOT -mode display, pin 9 may 
be left open; for BAR-mode, pin 9 is 
connected to the LED supply, which 



can 

Watch the IC's power dissipation in 
BAR mode, however. At 15 mA per 
LED, the LED supply should be no 
higher than 6 volts. To power the LED's 
from a higher-supply voltage, place a 
dropping resistor between the LED 
anodes and the supply. The LED supply 
should always be bypassed with a 10 yF 
electrolytic capacitor to prevent oscilla- 
tions. The LM3914"s + V supply (pin 3) 
must be at least t .5 volts above the pin 7 
reference output and can be as low as 3 



volts when the reference is run at 1.25 
volts (pin 8 grounded). 

Simple voltage monitor for TTL 

The LM39I4's low voltage-require- 
ments and flexibility make for some in- 
teresting applications. Figure 2 shows 
an expanded -scale voltage monitor for a 
TTL system that runs off the same 
single 5-volt supply it monitors! As 
shown in the table, each LED covers a 
I00-mV range from 4.5 to 5.5 volts, A 
simple two-step calibration is all that's 
required. 

Here the supply voltage is attenuated 
by a factor of two and fed to the LM3914 
signal input. Resistor R6 sets the top of 
the internal divider network at 2.705 
volts (5.41 V/2) and potentiometer R4 
sets the bottom of the divider at 2.205 
volts (4.41 V/2). Adjust R6 until LED 10 
just turns on with Vq C set at 5.41 volts. 
Then adjust R4 untilLED 1 just turns on 
with V cc set at 4.41 volts. There's a 
slight interaction so that running through 
that procedure a second time may im- 
prove accuracy. 

TTL and CMOS-compatible under- 
voltage and overvoltage signals are pro- 
vided, which can be used to shut down a 
system before damage (to either data or 
hardware) occurs. Optional diode Dl 
protects the IC in the event the 5-volt 
supply leads are reversed. For a simple 
go/no-go display, use red LED's at pins 
1 and 18 for undervottage and overvolt- 
age and wire-OR pins 10 through 17 to 
the cathode of a single green LED. 

Audio metering 

A logarithmic scale using the decibel 
(dB) is a convenient and popular one for 
measuring audio levels. A 3-dB increase 
corresponds to a 4 1 percent voltage in- 
crease and a doubling of power. The 
LM3915 features a (22K ohm) logarith- 



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FIG. 3— AUDIO-LEVEL METER displays the Instantaneous value of the audio Input signal. The LM3915 
provides a logarithmic response. 



GND 




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* 



-15dB 
LED4 



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* 



WH 



-12db 

LE05 



-SriB 

LFU6 
15 



-FJdB 

LED7 
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-3dB OdB 
LEDB LE09 
13 12 



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+3dB 

LE0 10 



LM3915 






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REF 

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R3 
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3 
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— v*. • H ? <> 

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:- 1DQK 



B4 

I DDK 



R5 
1.2K 



tf 



RFJ 

5K 



FIG. 4— PEAK-READING AUDIO-LEVEL METER is obtained by using a peak-detecting circuit on Input 
pin 5. 

INPUT DISPLAY 




DC SIGNAL-*- 



«7K 



A/V 



2V O 


• 


O— - 


„„o 


2.6V Q 


• 


•____ 


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A 1)1 



MODULATING 

VOLTAGE IN 

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TRIANGLE Oft SINE WAVE) 



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INPUT 
2V 4 



2.5V 



DISPLAY 
O— . 



.o 
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3V « * 
LED - 1 - 2 



-10 




RG. 5— INCREASED DISPLAY RESOLLTTION Is obtained by modulating the Input signal on pin 5 with 
either a sine or triangular waveform as shown In a. The resulting display shown In b and c has twice 
the original resolution. (The display shown In 6 obtained In the dot mode, while the display shown In 
c is obtained in the bar graph mode.) The same effect Is obtained with the logarithmic LM3915 by 
using the configuration shown In d. 



mic voltage-divider for a 3-dB-per-step 
display; otherwise, it's identical to the 
LM3914. The LM3915 is useful for dis- 
playing signals with wide dynamic 
range, such as RF signal strength, 
power level, or light intensity, in addi- 
tion to audio level. 

Figure 3 illustrates how simple it is to 
construct an audio-level indicator with 
the LM3915. The audio is fed straight to 
the IC's signal input without any rectifi- 
cation. Using the dot mode, the LED 
illuminated represents the instantane- 
ous value of the audio waveform. Both 
peak and average levels can be easily 
discerned. Since the dot will be con- 
stantly moving, the LED's are run at 30 
mA for adequate intensity. The full- 
scale reading (+3 dB) is 10 volts; that is 
easily altered by changing R2. The 
LM3915's signal input can withstand 
signals up to ±35 volts, which corre- 
sponds to 150 watts peak into an 8-ohm 
load. If there is a chance that the audio 
input could exceed this range, either at- 
tenuate it or include enough series re- 
sistance to limit the current to 5 mA. 

If a peak- reading meter is desired. 
Fig. 4 shows how it's done. Since the 
thresholds for the first few LED's are 
less than 1 vol t, a simple diode-capacitor 
peak detector won't do. The diode's 600 
mV turn-on threshold would not pass 
low-level signals. In the circuit shown, 
the voltage drop across Dl is can- 
celed out by the emitter-base voltage of 
PNP transistor Ql, connected as an 
emitter follower. These voltages usually 
track within 100 mV, causing a small 
error at low input levels. 

The LED connections in Fig. 4 illus- 
trate a tricky way to get a bar-graph 
display with very low current drain. 
With pin 9 left open, the LM3915 thinks 
it's in dot mode, so only one output will 
be on at a time. For an input between 
—24 and —21 dB, the pin- 1 current 
source turns on, lighting up LEDt. 
When the input increases to -21 to —18 
dB, the pin- 18 current source turns on 
while pin 1 turns off. With the LED's in 
series, the pin-18 output current flows 
through LED2 and LED1, lighting them 
both. For every 3-dB increase in input 
voltage, the current shifts over to 



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LED1 18 Tit [is lis |i« In \n T" M° ib u Ti6 is 14 n 12 n 10 




FIG. G — TWO LM3915's can be cascaded together to obtain wide dynamic range. The circuit i 
above la a peak-reading audio-level meter wtth a dynamic range of 60 dB. 



®' 




15 



($)W($)W(g ;• 



12 



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R4 ■ 
10012 



LM39I4 OR LM3915 






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INPUT 
t.25V 
FULL 
SCALE 



Rti 



R2 
47011 



3T0 6V 



R3 
IK 




:j_ci 

'IOQjiF 




;G2 




FIG. 7— OVERRANGE INDICATION with the bar-graph display is obtained with the above circuit. When 
the overrange condition occurs, the LED's flash. 



another output pin and lights another 
LED. That results in a bar-graph display 
that draws only 20 mA while lighting ten 
LED's, instead of 200mA for the stan- 
dard bar-graph configuration. A higher 
supply voltage is required, however, be- 



cause all the LED forward voltages are 
in series. The IC still stays coot since the 
current drain is low. That connection 
may be useful when "stealing" power 
from pre-existing stereo equipment that 
cannot supply much current. 



Other display ideas 

For increased resolution, modulate 
the LM3914's input signal with an AC 
voltage as in Fig. 5-a. The LED's will 
appear to turn on gradually, producing a 
display that changes smoothly like a 
meter. For the modulating voltage, a 
triangle wave works best, although a 
sinewave (60 Hz from a transformer, for 
example) can be used. The peak-to-peak 
amplitude of the AC voltage should be 
equal to the voltage step between 
LED's. Figures 5-b and 5-c depict the 
resulting displays in either the bar or dot 
mode. To obtain the same effect using 
an LM3915, where the voltage step be- 
tween LED's varies, one should modu- 
late the R HI voltage by 3 dB as in Figure 
5-d. 

Most program material has a dynamic 
range of over 40 dB. It's a simple matter 
to obtain a 60-dB display by cascading 
two LM3915's together, as shown in 
Fig. 6. A better peak-detector circuit is 
required because the threshold for the 
first LED is only 15 mV! The precision 
peak detector uses op-amp IC3 to over- 
come diode offset error. Operational 
amplifier IC4 is run at a gain of 30 dB or 
31.6. BiFET op-amps, such as the 



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THESE JIBE NO! 
HOME MADE TRAHWG DEVICES. 
THESE ABE PRODUCTION MODEL 

MICROSYSTEMS. 

HO OTHER HOME STUDY SCHOOL 

OFFERS THEM EXCEPT HIS. 

//////////////mi liiiimummn 


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IN FACT, NTS ELECTRONICS 
PROGRAMS INCLUDE THE 
WIDEST ARRAY OF SOLID STATE 
AND DIGITAL EQUIPMENT EVER 
OFFERED BY ANY HOME STUDY SCHOOL. 



Simutated TV Reception 



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testing this remarkable instrument and, best of all, we'll 
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It's the perfect opportunity for you to learn BASIC 
high level language programming and assembly 
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Then, to learn how to localize microcomputer problems 
and solve them, you'll experiment and test with a digital multi- 
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But most important, you get to assemble and work with 
today's most sophisticated microcomputers, not home-made 
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relevant and exciting. 

In fact, production-model equipment is featured in all 
NTS electronics programs. 

Our Color TV servicing program boasts the NTS/HEATH 
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In Communications Electronics you'll build and keep an 
NTS/HEATH 2-meter FM transceiver, along with digital multimeter and service trainer. 

Whichever NTS electronics program you choose, you can count on working with much 
the same kind of equipment you'll encounter in the field. 

Find out more in our full color catalog on the program of your choice. 

NTS also offers course in Auto Mechanics, 
Air Conditioning and Home Appliances. Check 
card for more information. 










>4 i 'Si , ti« 




fP/7/7 






IIULTlWTEB M"* 11 


') "*' '• 








Dtgttaf Multimeter 



NATIONAL 

TECHNICAL 

SCHOOLS 

TECHNICAL-TRADE TRAINING SINCE 1 BOS 

R*»id«nt and Herr^n. Study Schools 

4000 HI. FICUEBOA ST.. LOSAMCELES. CA. 90037 




""ftS! 



« •"'833k»" 



1. The NTS/HEATH H-89 Microcomputer features floppy disk stor- 
age, "smart" video terminal, two Z80 microprocessors, I6K RAM 
memory, expandable to 48 K. Available in NTS's Master Course in 
Microcomputers. 

2. The NTS/Rockwell AIM 65 Microcomputer A single board unit 
featuring an on-board 20 column alphanumeric printer with 20 
character display. A 6502-based unit4K RAM, expandable. 
Available in NTS's Microprocessor Technology Course. 

3. The NTS/KIM-1 Microcomputer A single board unit featuring a 
6 digit LED display with an on-board 24 key hexadecimal 
calculator- type keyboard. A 6502 based microcomputer with IK 
of RAM memory, expandable. Available in NTS's Master Course in 
Electronic and industrial Technology, 



NO OBLIGATION. NO SALESMAN WILL CALL. 
APPROVED FOR VETERAN TRAINING. 




NATIONAL TECHNICAL SCHOOLS 

4000 South Figueraa Street. ospt. 206- 100 
Los Angeles, California 90037 

Please rush FREE color catalog on course checked below 

D Auto Mechanics 
□ Air Conditioning 
D Home Appliances 



□ Microcomputers/ Microprocessors 
D Communications Electronics 
D Digital Electronics 

□ Industrial Technology 



Name 



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Age 



Address 
Apt 



.City 



Zip 



State 

D Check if interested in G.I. information. 

P Check if interested ONLY in classroom training in Los Angeles. 



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LM391 5 



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330K 



9.1K 



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R4 
4.7 K 



FIG. 8— TEN-STEP TIMER CIRCUIT. The LED's turn off sequentially, with each LED representing the 
time constant of R1 — C1. 






01. 0,3: ZN39H6 OR 2N2907 
02: 2N3904 OR 2N2222 
::■ i. 1N40Q1 OR SIMILAR 

"PICKR9 = +V-15INKn 
CYCLE TIME = 10XR2XC1 




Ra 
1DK 



LOGIC 

SUPPLY 0-6 

HIGH VOLTAGE OR 
HIGH CURRENT NPN 



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~ CONSTANT CURRENT 
SOURCE 



^ FIG. 9— N I N E-STEP SEQ U ENC E RT S a variation of the principle used i n t he ten-step t i me r s how n i n Fi g . 
cc 8 and can be used to turn various loads on and off sequentially. 

104 



LF35], that combine low bias current 
with a high slew rate are recommended. 
The offset-adjust pot Rl 1 is adjusted for 
a 0-volt output from IC4 with no audio 
input applied. 

As that example shows, the LED's 
can be run from an unregulated, unfil- 
tered power supply. The 6. 3-volt center- 
tapped transformer, and diodes D 1 and 
D2, provide a full-wave rectified voltage 
of about 4 volts to the LED anodes. That 
greatly reduces the load on the V + sup- 
ply in the bar-graph mode and also re- 
duces heat dissipation in the LM3915 
integrated circuits. 

In this circuit, resistor R7 sets the 
reference voltage for both IC's, Since 
both IC's have identical loading on their 
reference outputs, the reference voltage 
can be changed (from the [0 volts shown 
here) by lowering R5 without affecting 
the LED intensities. The time constant 
R3-C2 sets the display decay-time and 
can be optimized by varying the capaci- 
tance of C2. 

It's very easy to add an alarm that will 
flash the LED's when the input voltage 
exceeds full scale. The circuit is shown 
in Fig. 7. If desired, that scheme can be 
used to flash the display when the input 
voltage exceeds the threshold of any of 
the ten LED's, by simply moving the 
resistor-capacitor network (made up of 
R2 and CI) over to a different output of 
the IC. 

Timers and sequencers 

Use an LM3915 to monitor the volt- 
age on a discharging capacitor, as in Fig. 
8, and you've got a simple timer. Even 
though the capacitor voltage decays to 
zero logarithmically, displaying it via 
an LM39I5 results in equal time steps. 
Each time step is approximately Rix 
Cl/3. 

The sequencer shown in Fig. 9 is a 
variation on that. Capacitor CI is 
charged linearly by the current source 
made up of Ql, LED11 and Rl. When 
output 10 starts to turn on, Q2 and Q3 
conduct and CI is rapidly discharged. 
Cycle time is about lOxRlxCl. The 
LM39I4 outputs could be used to drive 
relays, opt o- isolators, or logic circuits, 
for example. 

Other ideas 

Don't think the LM3914 and LM39I5 
can drive only bars of LEDs. The LED's 
can be arranged in circles, or as X-Y 
displays, for instance. LCD's, vacuum 
fluorescents, and low-current incandes- 
cent bulbs can also be driven. As the 
examples show, outputs may interface 
with CMOS, TTL, opto-isolators and 
relays for a variety of automatic 
measurement and control functions. 
The decibel display of the LM3915 is 
especially attractive for audiophiles. 
Like the op-amp, applications of those 
display drivers are limited only by the 
imagination of the designer. R-E 



PIONEERS OF RADIO 



NIKOLA TESLA 



TESLA IS BEST KNOWN (BY THOSE WHO 

know of him at all) as the genius who 
conceived, invented, designed and put 
into operation our alternating current 
electrical system, without which much of 
the Electrical Age would never have 
come into being. That invention — or se- 
ries of inventions — freed the world from 
dependence on direct current, which lim- 
ited the distance that power could be 
transmitted to a mile or two from the 
generating station. 

Others know him as a dreamer who 
proposed such grandiose schemes as ex- 
citing the earth at its fundamental fre- 
quency and thus transmitting informa- 
tion — or even power — to any part of the 
globe, with little loss. Yet he was also the 
practical engineer who designed the com- 
plex Niagara Falls project, for many 
years the world's largest generating 
plant. 

As for grandiose projects, his genera- 
tion in 1899 of more than 12 million volts 
at his Colorado Springs laboratory (Ra- 
dio-Electronics, June 1976) was un- 
matched for more than 70 years. Experi- 
menting with wireless power transmis- 
sion, he lighted a bank of 200 lamps (us- 
ing about 10 kilowatts) 26 miles from the 
Colorado Springs installation. That feat 
has yet to be duplicated: 

These fantastic accomplishments have 
overshadowed his very real work in the 
radio field. Yet he was one of the first to 
work with high frequencies, and many 
engineers know him only by that first 
radio- frequency transformer, the Tesla 
coil. That "coil" was invented in 1891. In 
1893, speaking to the members of the 
Franklin Institute in Philadelphia, he dis- 
cussed electrical resonance, among other 
subjects. Pointing out that if the induc- 
tive and capacitive reactance in the circuit 
were such as to cancel each other, reso- 
nance would be attained and current 
would increase without a theoretical lim- 
it. He explained that it was fortunate that 
pure resonance could not be produced 
(because of resistance in the circuit). 
Otherwise, he said, there would be no 



FRED SHUNAMAN 



telling "what dangers might not lie in 
wait for the innocent experimenter." 

Concerning resonance, he said few 
words on a subject "that concerned the 
welfare of all. I mean," said Tesla, "the 
transmission of intelligible signals and 
perhaps even power to any distance with- 
out the use of wires. I am becoming daily 
more convinced of the practicability of 
the scheme." Admitting that most scien- 
tific men had doubts, he said "My convic- 
tion has grown so strong that I no longer 
look on this plan of energy or intelligence 
transmission as a mere theoretical possi- 
bility, but as a serious problem in electri- 
cal engineering, which must be carried 
out some day." 

Tesla continued to work with reso- 
nance, and his patent 568,178 of Septem- 
ber 22, 1896 shows several ways of 
obtaining resonance in a high-frequency 
circuit. In 1915 he sued Marconi for 
infringement of that patent, but lost the 
case. The court just could not understand 
the principles involved, and was possibly 
influenced by Marconi's reputation as a 
great man in communications. (The Mar- 
coni patent was, however, declared inval- 
id in 1943, on the basis of prior work by 
Tesla and the 1896 patent, as well as later 
patents by John Stone Stone and Oliver 
Lodge.) 

In 1899 Tesla staged a demonstration 
of radio remote control in Madison 
Square Garden, New York City. He 
maneuvered a three-foot-long model boat 
in a large tank, starting, stopping, revers- 
ing and steering it in response to requests 
from members of the audience. 

The Madison Square Garden transmis- 
sions were spark. But in his studies of 
high frequency, Tesla pioneered two oth- 
er types of transmitters that later became 
commercial successes in other hands. He 
made the first high-frequency alterna- 
tors, machines like ordinary alternating 
current generators, but designed to pro- 
duce electricity at much higher frequen- 
cies. Tesla's alternators reached 10 kilo- 
hertz. Improved by Fessenden and Alex- 
anderson, first to 50 and later to 100 



kilohertz, these alternators were made by 
General Electric and became the standard 
high-power transmitters for transatlantic 
and other long-distance communication, 
until displaced by tube transmitters. 

Tesla also pioneered in the use of the 
electric arc as a high-frequency genera- 
tor, describing one with controlled atmo- 
sphere and magnetic blowout in 1893. 
Re- invented by Valdemar Poulsen in 
1903, and introduced into the United 
States by Cyril F. Elwell, it became very 
popular, especially for medium and low- 
power transmitters and ship sets. (De 
Forest used the Tesla arc in his phone 
transmitters, because he could do so with- 
out infringing on the patents that were 
held by Poulsen.) 

In 1901 Tesla started the construction 
of an eight-sided wooden tower on Long 
Island. Surmounted by a copper- covered 
hemisphere 100 feet in diameter, it rose 
200 feet in the air. An air of mystery 
surrounded the tower and its purpose, but 
in 1 904 Tesla issued a brochure in which 
he described the project as a World Wide 
Wireless System, which he said would 
provide telegraph and telephone commu- 
nication, news broadcasting, stock market 
quotations, aids to navigation, entertain- 
ment and music broadcasting, accurate 
time service, facsimile and teleprinter 
services — in fact the whole gamut of 
radio services that was to come into exis- 
tence decades later. 

With the withdrawal of support by 
Tesla's financial backer — it is said be- 
cause he found that Tesla was more inter- 
ested in the new project as a transmitter 
of wireless power than wireless communi- 
cations — it became impossible to com- 
plete the work, and the tower was finally 
taken over by the Waldorf-Astoria in 
payment for a hotel bill, and torn down 
for scrap in 1917. This ended Tesla's 
radio work, and (though he continued to 
invent in other fields, such as steam tur- 
bines and even auto transmissions) 
marked the end of his career as an impor- 
tant scientist and engineer. He died in 
se m i - poverty i n 1 9 43 , R-E 



O 
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105 




Hafier Model DH-200 
Stereo Power Amplifier 



CIRCLE 106 ON FREE INFORMATION CARD 



LEN FELDMAN 

CONTRIBUTING HI-FI EDITOR 



TO THOSE OF US WHO HAVE BEEN SURVEYING 

the high-fidelity scene for many years, the 
name David Halter should be familiar. It was 
Mr, Hafier who founded the well-known Dy- 
naco firm which, for many years, offered high- 
quality reasonably-priced audio components in 
both kit and assembled form. As is true of 
many other American audio pioneers (such as 
Saul Marantz, Avery Fisher, and Sidney Har- 
man, for example), David Hafier has long since 
sold his interest in his first company and has 
been active in the field both abroad and in this 
country. A couple of years ago, he founded the 
present David Hafier Company whose second 
major product is the model OH -200 power 
amplifier {the first product was and is a low- 
cost high-performance prcamp, model DH- 
101. that makes a good companion piece for 
the newly introduced DH-200). 

The front panel on the DH-200 is shown in 
Fig. 1 and is equipped with a lever-type power 
on/off switch that is adjacent to a power-indi- 
cator light. Heat-sink structures at the left and 
right of the unit form an attractive and practi- 
cal cosmetic touch to the rugged-looking am- 
plifier chassis. The rear panel of the amplifier, 
shown in Fig. 2, contains 5-way binding-post 




terminals for speaker-cable connections, pho- 
no-tip jacks for input connections and a pair of 
speaker fuscholdcrs. Additional fuses arc lo- 
cated inside the chassis in the DC power sup- 
ply lines feeding each module or amplifier 
channel, as can be seen clearly in the internal 
view of Fig. 3. 

If you should elect to build the DH-200 by 
purchasing it in kit form, you will be surprised 



to find that two completely assembled and ful- 
ly tested amplifier modules comprise all of the 
kit's active circuitry. That leaves only a hand- 
ful of parts (largely power-supply components) 
for the builder to complete lhe mechanical 




assembly and power-supply wiring. The entire 
project can be completed by a reasonably expe- 
rienced electronic-kit builder in one sitting. 
Furthermore, should service ever be needed, 
you can easily remove and return one of the 
lightweight amplifier modules without having 
to return the entire unit. You can even operate 
the remaining module monophonically white 
waiting for the repaired module to be returned 
for servicing. 

The DH-200 has a unique circuit configura- 
tion using all discrete transistors, including 
power MOSFET's in the output stages. Like 
the Hafier preamplifier that preceded it, the 
DH-200 power amplifier has a completely 
symmetrical, mirror-image complementary 
push-pull circuit from input to output. For 
applications requiring extraordinarily high 
power, the DH-200 may also be "bridged" to 
convert it to a 300-watt monophonic amplifier 
(into an 8-ohm load) with distortion specifica- 
tions similar to those obtained in stereo. 

Lab measurements 

Tabic I summarizes the static measurements 
made on our prewired sample. The amplifier 
delivered more than its rated 1 00-watls-per- 
channel at all frequencies before the 



MANUFACTURER'S PUBLISHED SPECIFICATIONS: 
FTC Power Rating: Less than 0.02% total harmonic distortion at any power 
level up to 100 watts; continuous average power-per-channel into 8-ohms, at 
any frequency between 20 Hz and 20 kHz, with both channels driven. Typical 
THD: 100 watts into 8-ohms: 0.0015% at 1 kHz; 0.005% at 10 kHz; 0.009% at 
20 kHz. Frequency Response: — 3dB, 1 Hz to 100 kHz at 1 watt; ±0.5 dB, 10 
Hz to 40kHz at 100 watts. Input Impedance: 22,000 ohms. Input Sensitivity: 
1.5 volts for rated output. Damping Factor: 150 up to 1 kHz into 8 ohms; 50 
up to 10 kHz into 8 ohms. Rise Time: 2.5 microseconds, for a 10 kHz, 60 V 
P-P squarewave (10% to 90%). Slew Rate: 30 V/usec for a 10 kHz, 60 V P-P 
squarewave. 



RADIO- ELECTRONICS AUDIO LAB 

R.IE.A.L. 
SOUND 

MUMBLE RATES i^BLBBHi 

HAFLER DH-200 
POWER AMPLIFIER 

EXCELLENT 

Copyright f Gcrnsback Publications Inc., 1973 



nominal 0.02% harmonic-distortion rating was 
reached. In fact, wc were somewhat frustrated 
in attempting to measure all forms of distor- 
tion at the 100-watl output level. Our IM and 
THD test signal sources are known to contain 
approximately 0.002% distortion and those 
were the readings we obtained, indicating that 
the test equipment was imposing a limiting 
factor to our measurements. The same held 
true for our attempts to measure I H F 1 M dis- 
tortion, where the dynamic range of our spec- 
trum analyzer is limited to around 70 dB (cor- 
responding to 0.03% distortion). Hence, we 
listed our measurements as "less than 0.002%" 
in the case of THD and SMPTK-IM and "less 
than 0.03%" in the case of the other two-tone 
IM measurements. 

Note thai in Table 1 we have measured 4- 
ohm performance only for a 1-kHz mid- fre- 
quency signal. That is not to imply that the 
amplifier is unsuitable for use with 4-ohm 
speaker systems. Quite the contrary; it will 
operate safely even at impedances below 4 
ohms. The only reason we omitted any mea- 
surement reports for the frequency extremes at 
20 Hz and 20 kHz is because Hafier docs not 
supply a published distortion rating over the 
entire power band for 4-ohm operation. There- 
fore, we had no reference THD level against 
which it would be possible to measure output 
at that low impedance. 

In an introductory paper concerning the 
design philosophy of the Hafier DH-200, that 
company introduces yet another interesting 
performance test described by Malti Otala, the 
well known Finnish engineer who has written 
extensively on TI M distortion as well as a new 
form of distortion known as J IM (Interface 
Intermodulation Distortion). As explained in 



106 



that paper, the active load presented by a loud- 
speaker cannot be evaluated easily and is any- 
thing but a pure resistance, which most or us 
use on the test bench as an amplifier load. To 
simulate the loudspeaker as a generator, sig- 
nals must be driven into the amplifier output. 

While conventional theory has it that the 
low impedance (high damping factor) of high- 
fidelity amplifiers will "short out" the back 
electromotive-force of the loudspeaker, in ac- 
tual practice the low-output impedance of an 
amplifier is not a physical impedance. It is the 
result of feedback that may vary during the 
signal cycle and permit some of the loudspeak- 
er-generated signal to gel into the feedback 
loop and mix with the source signals. 

Olala proposes a method to measure what he 
calls Interface Intermodulation Distortion. In 
his lest setup, the amplifier is driven with a 
1-kHz signal. Simultaneously, the output of 
the amplifier is driven with a 60-Hz signal 
through an isolation resistor and a 1-kHz trap. 
A spectrum analyzer at the amplifier output 
shows both signals (60 Hz and I kHz) that are 
used for the test plus any other signals appear- 
ing at other frequencies. The latter are the 
intermodulation products caused by the inabil- 
ity of the amplifier to handle the reverse sig- 
nals without distorting. 





In a further effort to separate the DH-200 
from run-of-the-mill power amplifiers, we de- 
cided to try that test. The results we obtained 
using the DH-200 are shown in the photo of 
Fig. 4. The trace shows the 60-Hz signal at the 
left, the I -kHz signal near ccnterscrcen, and 
very little else. Compare those results with 
those obtained using a well-known amplifier 
having the same power rating, driven to exactly 
the same composite power level (approximate- 
ly half rated output in each case), as shown in 
Fig. 5. 

Summary 

Hafler maintains that the goal in the ign 
of the DH-200 was to reduce all known orms 
of distortion to their lowest possible values and 
to apply feedback with discretion, after first 




TABLE 1 
RADIO ELECTRONICS PRODUCT TEST REPORT 

Manufacturer: David Hafter Company Model: DH-200 

AMPLIFIER PERFORMANCE MEASUREMENTS 



POWER OUTPUT CAPABILITY 
RMS power/channel, 8-ohms, 1 kHz (warls) 
RMS power/channel, 8-ohms, 20 Hz (watts) 
RMS power/channel, 8-ohms, 20 kHz (watts) 
RMS power/channel. 4- ohms, 1 kHz (watts) 
RMS power/channel. 4-ohms, 20 Hz (watts) 
RMS power/channel, 4-ohms, 20 kHz (watts) 
Frequency limits for rated output (Hz-kHz) 
Slew rate (WMIcrosecond) 



RE 


R-E 


Measurement 


Evaluation 


114 


Very good 


108 


Excellent 


106 


Excellent 


161 


Excellent 


N/A 


N/A 


N/A 


N/A 


15-25 


Very good 


35 


Very good 



DYNAMIC HEADROOM (dB) 

DISTORTION MEASUREMENTS 
Harmonic distortion at rated output, 1 kHz(%) 
Intermodulation distortion, rated output (%) 
Harmonic distortion at 1 watt output, 1kHz (%) 
Intermodulation distortion at 1 watt output (%) 
CCIRIM distortion {%) 
IHF IM distortion <%} 

DAMPING FACTOR AT 8 OHMS, 50 Hz 

INPUT MEASUREMENTS 

Frequency response, (Hz-kHz, — 3dB) 

IHF input sensitivity (V) 

Input sensitivity for rated output (V) 

IHF S/N (Re: 1W Out, "A'-weighted) (dB) 

S/N Re: Rated Output, "A"-welghtedj (dB) 

POWER CONSUMPTION 

Idling (watts) 
Maximum (watts) 



1.9 



N/A 



Less than 0.002 


Superb 


Less than 0.002 


Superb 


Less than 0.002 


Superb 


Less than 0.002 


Superb 


Less than 0.03 


Superb 


Less than 0.03 


Excellent 


150 


Excellent 


1-109 


Superb 


0.15 


N/A 


1.5 


N/A 


91 


Excellent 


111 


Excellent 


118 


N/A 


540 


N/A 






TABLE 2 
RADIO-ELECTRONICS PRODUCT TEST REPORT 



Retail price 
Price category 
Price/performance ratio 
Styling and appearance 
Sound quality 
Mechanical performance 



$329,95 (kit); $429.95 (Assembled) 

Low 

Superb 

Very good 

Excellent 

Excellent 



Comments: What can one say about an amplifier that, despite its Incredibly low cost, yields levels 
of distortion (at all power levels within its ratings) that cannot be read on state- 
of-the-art test equipment such as that used in our R.E.A.L. tests? To be sure, static 
"bench" measurements often fall to correlate with what one hears when using an 
amplifier (or any other piece of audio equipment) for the reproduction of music. In the 
case of the Hafter DH-200, however, it Is clear that the more subtle forms of distortion, 
such as TIM and IIM (Interface Intermodulation Distortion), which have only recently 
been identified by researchers in the field, have also been reduced to an inaudible 
minimum, Hafler maintains that his circuit is self-protecting and that the output stage 
is designed to protect against thermal runaway, without any need for signal-interrupt- 
ing relays and the like. Indeed, during our bench tests, the only problem we encoun- 
tered was occasional popping of speaker fuses which were accessible for replacement 
from outside the amplifier. It was only after we read the preliminary owner's manual 
that we realized that the amplifier had been shipped with 2-ampere fuses (to protect 
speakers with iow maximum power ratings) and that we should have substituted the 
5-ampere substitute fuses that are supplied with the unit. Once that was done, the 
amplifier became virtually Indestructible. 

As for sound quality, we can state that the DH-200 offers bass reproduction as good 
as any we have heard from amplifiers costing hundreds of dollars more. Treble sound 
could also be characterized as free of any raspiness or slew-induced distortion, 
regardless of the transient content of the program material used for listening. 

Considering its low price (especially it purchased in kit form), we know of no other 
amplifier that offers as much value at the present time. Hafler's first product entry, the 
Model DH-101 preamplifier, has already earned itself an enviable reputation amongst 
knowledgeable and critical audiophlles. We suspect that the Hafler DH-200 power 
amplifier will earn a similar degree of respect from this same critical fraternity. The 
DH-200 deserves an R.E.A.L. overall product rating of excellent, bordering on 
superb. 



minimizing distortion of the open-loop circuit 
of the amplifier. Using feedback as a refine- 
ment (not a cure-all), according to Hafler, 
avoided some subtle forms of distortion such as 
those outlined in the test of IIM and yielded 
audibly better sound. We couldn't agree more. 
Our overall product evaluation, together with 
our summary comments concerning the David 



Hafler Company model DH-200 will be found 
in Table II. That amplifier, in our opinion, is 
not only extremely reasonable in price (partic- 
ularly in its kit version) but the sound is as 
good as anything we have ever heard, regard- 
less of price. It merits a R.E.A.L. Sound Lab 
product rating of "excellent", bordering on 
"superb." R-E 



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Applications 

The flasher LED is a new component Learn how it works 
and keep it among your arsenal of components for use 
when designing projects 



CALVIN R. GRAF, W5LFM 

THE FLASHER LED HAS RECENTLY BEEN IN- 

troduced into the electronic parts market. 
It is inexpensive and offers some very 
interesting possibilities for circuit innova- 
tion. This article describes some applica- 
tions of that simple device, which has its 
own built-in IC switch. With the use of a 
few components — a 9-volt battery, LED 
flasher, photocell and resistor — a series of 
novel circuits can be configured. They 
cover the areas of a continuous LED 
flasher for a night light, a basic flasher for 
TTL and CMOS circuit applications, 
attention -getter applications, a trouble- 
shooting aid, and ambient light or dark 
detecter. The Flasher LED is currently 
available at Radio Shack stores (part No. 
276-036). 

How it works 

The basic LED is made to flash at a 
three-times-per-second (PPS) rate by a 
small integrated circuit that operates off a 
5-volt DC power supply. The flasher 
LED is indeed unique when you consider 
that the LED is the same size as a regular 
LED but contains the following electrical 
components: the LED, the IC chip that 
establishes the flash rate (in effect con- 
taining an R-C time-constant circuit to 
switch the current to the LED), and an 
"effective resistor" that drops the supply 
voltage from 5 volts DC to a nominal 1.6 
volts DC for application to the red LED. 
The flasher LED draws 20 mA from a 
5-volt source, so for a normal red LED 
(which draws 20 mA) a series-dropping 
(current-limiting) resistor of 170 ohms 
would be required. So a lot is accom- 
plished by the small IC chip that can be 
seen as a small black speck inside the 
LED epoxy case. At the present time, the 
flasher LED is available with a red lens 
only but other colors — such as green and 
yellow — probably will be forthcoming 
from LED manufacturers. 




FIG. 1— LED FLASHER is powered from a 5-voll 
supply and fleshes at a 3-PPS rate. 
IK 

1/2W 
*o WV- 

// 



9 VDC 
BATTERY 



® 



FLASHER 
LED 



FIG. 2— POWER can be obtained from a 9-volt 

source if a dropping resistor is used, 
IK 
1/2 W 
"■vW- 




FIG. 3 — AC POWER can be used if a diode and 
dropping resistor are included as shown. 




FIG. 4— FLASH RATE can be varied with an R-C 
circuit. 

Applications 

Normal flash rate. In Fig. I we see the 
basic hookup for the LED IC Rasher 
operated off 5 volts DC. This configura- 
tion is used to drive the flasher directly 
off TTL and CMOS circuits and it will 
flash at a nominal 3 PPS. Note the elec- 
trical schematic symbol we have used for 



the IC flasher LED. We have added a 
small rectangle to the cathode symbol of 
the LED to differentiate it from a regular 
LED. Perhaps this symbol for the flasher 
LED will be adapted for wider use. Fig- 
ure 2 shows an arrangement for Hashing 
the LED from a 9-volt transistor battery 
at a 3-PPS rate. A 9-volt battery will pro- 
vide sufficient power to flash the LED for 
about a week, so for continuous operation 
you can use a 9-volt battery eliminator or 
charger available at radio supply houses 
for under $5,00. Note that in the circuit 
of Fig. 2 we have added a 1000-ohm 
scries resistor to drop the voltage across 
the flasher LED to a nominal 5 volts. The 
resistance value is not critical and the 
brilliance of the LED and flash rate will 
vary slightly with applied voltage as it is 
varied below 5 volts. 

An alternating current (AC) power 
supply of a nominal 6 to 9 volts can be 
used to power the flasher LED by adding 
a diode to the circuit to protect the LED/ 
IC chip during negative voltage swings of 
the AC voltage. This circuit arrangement 
is shown in Fig. 3. The 6.3- to 9-volt AC 
power supply can be obtained by using a 
1 1 5-volt to 6.3 volt filament transformer 
or an AC pocket calculator charger which 
usually has a nominal 8-volts AC output. 

Fast flash rate. We can increase the 
flash rate by adding a large capacitor 
across the series- dropping resistor as 
shown in Fig. 4. The flash rate is 
increased to a nominal 10 PPS by the 
R-C circuit introduced in series with the 
IC chip. The capacitor can be any value 
from 500 to 3000 >iF at a nominal 10- to 
35-volts DC working voltage. Experiment 
with the value of R and C until you reach 
the flash rate you want. 

If the flash rale is increased to slightly 
above 10-to-12 PPS, the LED will appear 
to be on continuously as the eye cannot 
perceive faster flash rates. To observe the 



108 




LED flashing (if your circuit leads are 
long enough), wave the LED back and 
forth slowly and you'll observe it to make 
on on-off streak as it moves. 

Ambient light detector: When we put a 
photocell in series with the flasher LED 
as shown in Fig. 5, it will flash only in the 
presence of light. Photocells available 
from any radio-supply house have a nomi- 
nal resistance of l-to-10 megohms in 
darkness and their resistance drops rapid- 
ly to a nominal 100-to-1000 ohms in 
bright light. In darkness, the circuit will 
draw virtually no standby power as the 
total resistance in the circuit is over 1 
megohm. Considering the IC chip as a 
short at this time, the circuit will draw 
only 9 microamperes from the battery, 
virtually its shelf life. You can use this 
circuit to tell you when it gets dark out- 
side (if you are in a windowless room) or 
it you really want to see if the refrigera- 
tor light goes out when the door is closed! 
For light levels in between light and dark, 
where the applied voltage to the IC chip 
will vary from 0-to-5 volts, we will find 
the flasher LED doing some strange 
things such as flashing faster, slower, 
staying on or off, and varying its bril- 
liance. 

When we place the photocell across the 
flasher LED as shown in Fig. 6, we now 
find that the LED will not flash in bright 

Eton 

mw 
+ ■* va 



light (the low resistance of the photocell 
shorts out the IC chip) but when the pho- 
tocell is in darkness, the LED will flash. 
In darkness the photocell resistance rises 
to about 10 megohms and this appears as 
an open circuit to the IC chip, 5 volts 
appears across the chip and the LED 
begins to flash. That circuit will draw 
power from the battery in the standby 
(light-present) condition and nominal 
power when flashing, so you might want 
to use a 9- volt battery eliminator for long- 
time operation. This circuit is handy for a 
flashing night-light in use in hallways and 



4.7K 
1/2W 



+ o — 

FLASHI 
SVOC LED 

BATTERY 



© 



& 




PHOTOCELL 



FIG. 6— PARALLEL PHOTOCELL permits LED 
to flash only in dark ambient light conditions. 




JK t/2W 
— W» — 



9VDC 
BATTERY 



PHOTOCELL 



<u 



if 



FLASHER 
LEO 



PIG. 5— SERIES PHOTOCELL permits LED to 

flash only in bright ambient light conditions. 



J-6VDC 



60 ^j: 

16VDC ^ 



® 



# 



® 



'RED 
FLASHER 
LEO 



GREEN LEO 



680R %. £?«f„ 

r* 16VDC 



RED AND GREEN LEOS FLASH ALTERNATELY 

AT RATE DETERMINED BY APPLIED VOLTAGE 

FIG. 7— RED AND GREEN LED's flash alternately at a rate determined by the applied voltage. 



other locations or areas where you might 
need to know that a certain light is still on 
and operational. 

Alternate flashing red and green 
LED's: The flasher LED can be used in a 
circuit arrangement as shown in Fig. 7 to 
alternately flash a second LED. The two 
LED's can be spaced several inches or 
feet apart to attract your eye back and 
forth to each LED as it flashes. Alter- 
nately flashing red and green LED's are 
particularly interesting as they are eye- 
catching and can serve as baby sitters, 
novelties, or attention -getters. The circuit 
of Fig. 7 will operate from a nominal 3- 
to-6 volts DC, the flash rate increasing as 
the voltage is decreased. At 6-volts DC, 
such as you get from a Type-F lantern 
battery available at hardware stores, the 
flash rate is the nominal 3 PPS. If the 
circuit voltage is increased past 6 volts, up 
to 7 or 8 volts, the LED's will stop flash- 
ing and remain on continuously. That 
condition should be avoided for use over 
long periods of time as it might damage 
the IC chip in the flasher LED. 

As the voltage is reduced to about 3 
volts, the flash rate increases to about 1 
PPS and the LED's are not as bright as at 
6 volts. The LED's will flash faster and 
faster as the voltage is reduced below 3 
volts until they appear to be on continu- 
ously, though they are dim at this time. 

As you experiment and work with the 
flasher LED, you will find it a very inter- 
esting electronic component. You may 
observe that its flash- rate changes, de- 
pending on the amount of ambient light 
striking the IC chip inside its epoxy case. 
Depending on the manufacturer of the 
LED, the flash rate will be a nominal 3 
PPS in bright bench light or sunlight. But 
as you darken the room, the flash-rate 
will decrease slightly, depending on the 
circuit you are using at the time. Do your 
own experimenting with this unique de- 
vice until the manufacturers correct for 
some of its interesting characteristics! ° 
They might add a Zener voltage-regula- ^ 
tor to keep the flash-rate constant with j*> 
applied voltage and then hide the IC chip 33 
in a lightproof case — and that would take 5 
away all the fun! B-E o 

109 



to 
o 

z 

o 

DC 
H 
O 



PC-BOARD BUBBLE ETCHER 

MY NEW IDEA INVOLVES CONSTRUCTION 

plans for an inexpensive (under $10) bub- 
ble etcher that reduces the time to etch 
printed circuit boards considerably. The 
materials required for the etcher consist 
of a phenolic instrument case, Vis-inch 
OD rigid PVC tubing, instant-setting 



pieces of tubing, use a No. 76 drill to drill 
a .020-inch-diameter hole at each marked 
location. 

Upon completion of the drilling, re- 
move all loose fragments from inside the 
tubing, arrange the pieces into a 6'A-inch 
X 4- inch rectangle and cement the tub- 
ing ends together, being careful not to get 
cement inside the tubing. Let the cement 



— f'off G-tH 





■HOLES ON THIS SIDE 
FIG. 1 



1 ^"■j—i'—^—l' 



r—\ 



;<§ 



3/14" u \ 



2 PIECES -(W/f" LONGr 

FIG. 2 



r 



.OZO" D/A HOLE 
(o PLACES 





UJ 
■ 

Q 
Q 
< 

110 



PVC cement, an aquarium air pump, a 
piece of %-inch ID flexible plastic tubing, 
and a piece of plastic canvas of the type 
used for needlepoint. (The "canvas" has 
an open grid containing Vjj-in. square 
holes.) Any size etcher may be con- 
structed simply by cutting the length of 
PVC tubing to fit the case size. The etch- 
er described below uses a standard-size 
instrument case having inside dimensions 
of 6'A X 4 3I A= X 2V« inches. The PVC 
tubing, cement, flexible tubing, and plas- 
tic needlepoint canvas were purchased at 
a hobby and crafts store, the aquarium air 
pump at a pet store, and the case at an 
electronics parts supply house. 

The heart of the etcher is a rectangular 
air tube constructed from two 6'A-inch 
and two 4-inch lengths of the rigid PVC 
tubing (these dimensions fit the case I 
used). The ends of each piece of tubing 
are cut at a 45° angle as illustrated in Fig. 
I. Refer to Figs. I and 2 and mark the 
locations of the air holes in the 6'A-inch 



*+s'-J5F 




dry before going to the next step. 

At the top center of one of the 4-inch 
legs of the rectangle, drill a 'At-inch- 
diameter hole through one wall of the 
tubing and remove any loose fragments 
from inside. Next cut a t'A-inch length of 
tubing and cut a notch in it about 'As-in. 
wide by 'At-inch deep, centered across 
one end as shown in Fig. 3. Align the 
notch parallel to the length of the drilled 
4- inch, tubing and cement the notched 
continued on page 122 



NEW IDEAS 

This column is devoted to new ideas, 
circuits, device applications, construc- 
tion techniques, helpful hints, etc. 

All published entries, upon publica- 
tion, will earn $25. In addition, Panavise 
will donate their model 324 Electronic 
Work Center, having a value of $49.95. 
It combines their circuit-board holder, 
tray base mount, and solder station (see 
photo below). Selections will be made at 
the sole discretion ol the editorial staff 
of Radio-Electronics. 




I agree to the above terms, and grant 
Radio-Electronics Magazine the right 
to publish my idea and to subsequently 
republish my idea In collections or com- 
pilations of reprints of similar articles. I 
declare that the attached idea is my 
own original material and that Its publi- 
cation does not violate any other copy- 
right. I also declare that this material 
had not been previously published. 



Title of Idea 



Signature 



Print Name 



Date 



Street 



City 



State 



ZIP 



Mail your idea along with this coupon 
to: New Ideas Radio- Electronics, 

200 Park Ave. South, 

New York, NY 10003 



Sabtronics NEW Hand-held Digital Multimeters. . . 



The only thing that 
beats their performance 
is their price. 



Accurate performance you can rely on, time 
after time. That's what you expect from a 
quality DMM. But don't expect to pay as 
much for it any more. Because now Sab- 
tronics brings you top quality DMMs with 
more features and better accuracy than 
other comparable units on the market to- 
day. And they cost surprisingly less! 

We cut the price. 
Not the quality. 

What you get is a precision crafted unit that 
features single-chip LSI logic, laser trimmed 
resistor network and a stable band-gap 
reference element for better long term ac- 
curacy. Basic DCV accuracy is 0.1%. The 
Model 2035A gives you 32 measurement 
ranges over 6 functions and the Model 
2037A an additional two temperature 
ranges. 

First in features. 
First in price. 

Both models feature a "touch-and-hold" 
capability with the optional probe - a 
reading is retained for as long as you 
wish. Now you can make measurements in 
hard-to-reach places without taking your 
eyes off the probe tip or stopping to 
record data. 

The two-terminal input for all 
measurement functions eliminates 
switching lest leads when measuring voltage, 
resistance or current. The Model 2037 A even 
has a built-in temperature measuring 
circuit with a -50 °C to + I50°C range and 
is supplied complete with the sensor probe. 
It is ideal for checking 1C, resistor, transistor, 
heal sink and enclosure temperatures or for 



monitoring environmental lest temperatures. 

Plus more features. 

The Hi-and-Low power ohms capability 
allows you to make in-circuit resistance 
measurements and to check semiconduc- 
tor PN junctions. In addition automatic 
polarity, automatic zero, automatic 
decimal point and overload protection are 
standard features. And you get up to 200 
hours operation from a single 9V tran- 
sistor battery. The automatic "LO BAT' 
indicator warns you of the last 20% of 
battery life. The large, crisp LCD 
readouts allow easy viewing indoors or 
outdoors in bright sunlight. 

One-evening kit assembly. 

Assembling either kit is simple with our 
easy-to-follow, step-by-step instructions. 
The built-in calibration references allow 
you to calibrate the unit any time, any 
place. We've even eliminated difficult 
point-to-point interconnect wiring. All parts 
mount on the PC board. The only wires you 
solder are the two battery clip leads. 

Order yours now. 

With all of these features and perfor- 
mance characteristics no other handheld 
DMM comes even close to matching the 
price/performance ratios of the Models 
2035A and 2037A. Providing the best 
value for money in test equipment, Sab- 
tronics has become one of the world's 
largest producers of DMMs. You can 
order with confidence. Use the convenient 
order form or call us with your Master 
Charge or Visa number for prompt 
delivery. 




Making Performance Affordable 



INTERNATIONAL INC 



5709 North 50th Street, Tampa, Florida 33610 
Te I e pho n e 8 1 3/6 23 263 1 



BRIEF SPECIFICATIONS: 

DC VOLTS: 100* V 1000V. S ranges 

AC VOLTS: 1 00, V 1 00OV, 5 ranges 



l.u A - 2 A, 5 ranges 
In A - 2 A - 5 ranges 
20M<; , 6 ranges 
20M!» . 6 ranges 
-50°C- ♦ 150°C 



OC CURRENT: 0. 

AC CURRENT: 0- 

Hi-OHMS: 0.1 :. 

Lo-OHMS: 0.1; 

TEMPERATURE 

I -6B°F - + 302°Fl. 2 ranges 

[Model 203 7 A only] 

Size: I 'A "W x 6 >A ' 'L x ! 5/8 ' 'H 

WEIGHT: 1 1 oz. (end. battery) 
OVERLOAD PROTECTION: 1000V DC 
or AC peak all voltage ranges. 250V 
DC or AC peak all Ohms ranges; 
2A/250V fuse all current ranges. 



SABTRONICS SERVICE AVAILABLE 

IN MOST COUNTRIES OF THE 

WORLD 



To: Sabtronics International, Inc., 5709 North 50th Street, Tampa, FL 33610 

Please send me 



.Model 2035 A Handheld Multimeier kitts) <s (74.95 ea. 
.Model 2037 A Handheld Multimeier kit(s) a $99 95 ea 
.Shipping and handling ® S5.00 per kit (seehelow)t 
_Model THP-20 Touch-and-hold Probers) a SI 9,95 ea. 
.Model AC-n Battery Ellminator(s) <rf 1795 ea. 
_Model HVP-3030 kV DCHigh-vollage Probels) S S29 95 ea. 
Florida residents add 4% Stale Sales Tax 



I enclose U check" L money older Bill my U Master Charge U Visa 
Card Accounl # 



TOTAL 



Expiry da ie_ 



"Allow 2-3 weeks clearance lime lor personal checks. No COD. 
Name 



1 



Street 
Cny _ 



Slate 



Apt._ 
- Zip_ 



TConlinenral U.S. only AK, HI & PR: S6 00 Canada: S7.50 Foreign: S1 9.00 Airmail 



o 
o 

H 

o 

Cu- 
nt 
m 

o 

s 

111 



A one-chip (almost) digital panel meter in half an hour. 

EARL "DOC" SAVAGE, K4SDS, HOBBY EDITOR 



THERE IS A DIGITAL PANEL METER (DPM) 

IC on the market from Intersil (10710 
North Tanlau Avenue, Cupertino, CA 
95014). The 40-pin CMOS IC contains 
not only the 3'/:-digit A/D converter but 
also the 7 -segment decoders, display driv- 
ers, a reference and a clock. All you add is 
power, a few resistors and capacitors and 
a display to make a complete digital 
meter. Nothing could be simpler! 

The fact is that there are two such 
Intersil IC's: the ICL7106 for use with a 
liquid crystal display (LCD) and the 
ICL7107 for use with a LED display. 
These IC's are identical in function, but, 
because of drive requirements for the two 
types of displays, they use different pow- 
er (9 volts and 5 volts, respectively) and 
there are other internal differences. The 

7106 and 7107 are not interchangeable. 
Perhaps of greater interest are the 

available "evaluation kits," including all 
parts for a complete digital meter except 
power supplies. For example, the 7106 kit 
contains the IC, a 3'A-digit LCD, a PC 
board, 5 capacitors, 4 resistors, a pot and 
hardware (battery holder and connector, 
Molex socket pins and test lead jacks). 
About 30 to 40 minutes with your sol- 
dering iron and you have a working 0-200 
mi7/ivoltmeter. 

[The 7106 kit sells for $29.95 and the 

7107 kit sells for $24,95, Order these 
directly from your nearest Intersil dis- 
tributor. You can obtain a distributor 
listing by writing to Intersil at the 
address already given. — Editor] 

Recently, I assembled a 7106 kit. The 
instructions are quite clear, assembly is 
simple and the meter worked beautifully 
right from the beginning. The only tick- 
lish part of construction is getting the IC 
and LCD into the Molex pin socket. 



vt>c 



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9 
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HI 

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112 



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-o47l 



4oo fl £E*S* & ^Q 
p.. . 

R4 



RS - Rfrt 






TO 
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FIG. 2 



and one capacitor as per the instructions 
provided, I changed the DPM to read 0-2 
volls. It has to be calibrated and you can 
do this with another meter of known 
accuracy or with a fresh carbon-zinc 
(flashlight) battery that has a potential 
pretty close to 1.55 volts. 

For my purposes, the 0-2 volt instru- 
ment is really more useful — it measures 
from - 1 .999 V to + 1 .999 V. To mea- 
sure transistor bias (or almost anything 
else) just stick the leads into the circuit. 
Don't worry if you get them backwards; 
the meter changes sign from plus to 

DC VOLTMETER. 



f o- 



EtlT 



V 



inn n 
1 u il U 



± 



FIG. 3 



Patience and perseverance are the keys 
here. 

The ease of measurement and reading 
is as great as you would expect from a 
digital meter. First, the input resistance is 
very high so that delicate transistor cir- 
cuits are not upset when the test leads are 
introduced. Second, when did you last see 
an analog meter that measured to tenths 
of a millivolt! The 7106 kit, by the way, 
is well powered by a standard 9-volt bat- 
tery. Total current for the IC and the 
LCD is only about 1 mA, so battery life 
will be long. Of course, the 7107 kit 
requires considerably more current be- 
cause of the LED display. 

By changing the values of two resistors 



/ O O O 

I U LI U 

DIGITAL PANEL METER. 



if — ± 



FIG. 1 



minus and gives you the reading {actual- 
ly, no sign means a plus). You needn't 
worry, either, about ovcrvoltage. If it is 
greater than 1.999 volts or less than 
— 1.999 volts, the last three digits simply 
turn off to tell you of the overrange con- 
dition with no harm done. 

You can add a little voltage divider cir- 
cuit like the one in Fig, 1 if you want to 
be able to measure larger voltages. Note 
that the resistor values are approxima- 
tions. They should be adjusted to provide 
readings on the 20-volt and 200-volt 
scales (the 2-volt scale is already cali- 
brated). 

You can use a standard 10% resistor 
for Rl. If pots are used for R2 and R3 
(about 1 ,5 megohms and 1 50K), they can 
be adjusted easily. Again, the values can 
be measured and fixed resistors substi- 
tuted. 

The circuit of Fig. I makes no provi- 
sion for shifting the decimal point in the 
display. This can be accomplished by add- 
ing another section to the switch and wir- 
ing it to the DP terminals on the circuit 
board. You may also wish to add another 
switch to serve as an on-off switch for the 
DPM. 

To measure AC voltages, add the cir- 
continued on page 114 



An in-depth look at 
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?ver need for your home. 



FUNCTIONS: 
ON AND OFF 



FUNCTIONS: 

ON. OFF. BRIGHTEN 

AND DIM 




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Simply plug in The Controller™ 
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anywhere in the house by pressing a 
few buttons. So it's easy to take control. 

There's no end to all 

of the control you've got. 

You can turn on the TV, radio or 
stereo in the morning to help you wake 
up without getting up from bed. Or at 
night, turn on the lights before going 
downstairs so you don't have to fumble 
in the dark. Turn off unnecessary lights 
and help get your electric bill under 
control. Or, dim the lights and save 
energy, too. 

And when it's time to turn in, just 
push a button and turn everything off. 
And sleep soundly. But, if you hear a 
strange noise in the middle of the night, 
you can press a button to turn on all the 
lights and scare the daylights out of an 
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The Controller is designed to 
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By pressing the buttons on the 
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module of your choice. The Lamp 
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The Appliance Module turns 
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Module is designed to turn on, off or 
dim any light or lamp up to 500 watts 
normally operated by a wall switch. 

There's even a Cordless Controller 
that transmits signals to an Ultrasonic 
Command Console from up to 30 feet 
away. So there's plenty of control for 
everyone. 

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No special wiring is 
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Console into any wall outlet 
in any room of the house. 
Then plug your lamps and appliances 
into the appropriate modules. Plug in 



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113 



HOBBY CORNER 

continued from page 111 



cuit in Fig. 2. Although R4 is not critical, 
R5 is. You can make up a variable resis- 
tor by using fixed resistors and a high- 
value pot in series. Resistor R5 should be 
adjusted for correct calibration on one 
scale, say 20 volts, and the other scales 
will read approximate values. (This is one 
of the problems with this oversimplified 
circuit; the other is that the hundredth 
digit tends to jitter on AC but the earth 
ground helps in this regard.) If your 
major use of the AC meter will be to 
measure the line voltage, you should 
adjust R5 for greatest accuracy on the 
200-volt scale. 
Current may be measured with the 



wf- 
9 

z 
o 
cc 
t- 
o 

LU 
-i 

LU 
I 

Q 
Q 
< 
rr 



Intersil DPM just as with analog meters. 
(See "Hobby Corner," May 1980 issue.) 
The shunt resistor (R s ) is connected as 
shown in Fig. 3. Its value is found just as 
for the analog shunt. 

Greater sensitivity and less circuit 
effect would result, of course, if the 
basic DPM were left wired for 200 raV 
instead of 2-volts. Again, you should 
select a shunt value to make the current 
readings correspond with the voltage 
reading on the meter — there is no way 
you can put a new face on a dial that isn't 
there! 

Despite all they have to offer, these 
Intersil kits are quite reasonably priced. 
The ICL7107 LED kit is about $25 and 
the ICL7106EV, for LCD's, about $30. 

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Superb compact amp, same size as HV50, but 15 
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114 



(N CA_NADA^GIadstone Electronics, 173^Awnue_Rd., Tora j | W'Ji n .Uiiyil:IK:li 4 JL__Tfil4k. 
CHciuE 71 ON FREE INFORMATION CARD 



GX^&HKk 



More information on new 
lit is available. Use the 
Free Information Card inside 
the back cover 

SGL WABER MULTIPLE OUTLET STRIPS, Cafa- 
log 102, contains 24 illustrated pages. The new, 
completely-revised catalog gives detailed de- 
scriptions and specifications for 1 19 outlet-strip 
models. 65 of them UL-Listed and 28 CSA-Certi- 
fied. Multiple outlet strips are widely used in 
industrial, commercial, and military fields. They 
offer a quick, safe, and easy way to multiply, relo- 
cate, and switch-control outlets in an electrical 
branch circuit without changing the wiring. 

The catalog also includes typical application 
areas, examples of custom design, and general 
ordering information. — SGL Waber Electric, 300 
Harvard Ave., Westvllle, NJ 08093. 

CIRCLE 141 ON FREE INFORMATION CARD 

ELECTRONIC TEST ACCESSORIES, 1980, Is a 
100-page catalog with over 500 photos and over 
100 drawings. The products Include banana 
plugs, jacks, and patch cords; phone-tip jacks, 
plugs, and connecting cords; test clips, probes, 
and holders; binding posts, black boxes, and 
sockets; molded patch cords, cable assemblies, 
and test socket adaptors; V space molded 
accessories, molded test leads, and connecting 
leads. 

The catalog also includes new products, con- 
version tables of temperatures, a metric conver- 
sion chart. BNC and triaxlal cable procedures, 
and a cross-index of connector MIL numbers. — 
ITT Pomona Electronics, 1500 East Ninth Street. 
Pomona CA 91766. 

CIRCLE 142 ON FREE INFORMATION CARD 

MINIMICROMART CATALOG, for winter is a let- 
ter-size, illustrated booklet listing microcomput- 
ers, small computer systems, printers, kits, disk 
drives, terminals, floppy disk systems, memory 
boards, and other accessories for the hobbyist. 
Features and some specifications described. 
They also have a limited inventory of the now- 
discontinued Cromemco kits. — MiniMicroMart, 
Inc., 1618 James Street, Syracuse. NY 13203, 
CIRCLE 143 ON FREE INFORMATION CARD 

INSTRUMENTS FOR TESTING AND DESIGN, Is 
Global Specialties Corporation's new 36-page 
catalog. You will find here the company's well- 
known line of solderless breadboards, instrument 
cases, logic probes, frequency counters, and oth- 
er test and measuring instruments. 

Among the new products listed are the Univer- 
sal Counter-Timer [mode) 5001), suggested price 
$360; a benchtop 650 MHz Frequency Counter 
with a 0.1% crystal oven oscillator [model 6001\, 
suggested price $385; and a trlggerable 40-chan- 
nel multiple-threshold logic state indicator (model 
LM-3 Logic Monitoi), suggested price $585. Oth- 
er newcomers to the catalog are a breadboard 
wire jumper kit, Including prepared color-coded 
wires in 14 lengths designed for use with the com- 
pany's solderless breadboards in place of user- 
prepared hookup wires ($10), and a binding post 
assortment which Includes five red and five black 
binding posts, 20 insulating shoulder washers 
and 20 mounting nuts. These binding posts 
accept banana plugs, alligator clips, bare wire, tip 
continued on page 127 




More information on new products is available. Use the 
Free information Card inside the back cover. 



OSCILLOSCOPE, model LBO-515B, an up- 
graded version of the LBO-S15, has been in- 
Creased in bandwidth to 30 MHz and a 10-tum 
calibrated delay-time function control has been 
added. It features a 5 mV sensitivity In both 
sweep and X-Y display modes and dual-channel 




CIRCLE 1S1 OH FREE INFORMATION CARD 

displays which can be either chopped or alter- 
nated and the sum or difference of the channels 
Indicated. The trigger controls include selection 
of cn-1 and ch-s, AC- or DC-coupling, video frame 
or line sync filters and + or - slope selection, 
and includes a trigger holdoff control. The 4-inch 
CRT features an internal 8X10 graticule which is 
calibrated for measurement of risettme. The 
LBO-515B measures 11'A" x 5'A" x 14V. Acces- 
sories include a probe pouch and special-pur- 
pose probes. Price Is $1,530. — Leader Instru- 
ments Corp., 380 Oser Ave., Hauppauge, NY 
11787. 

VOLTAGE CONTROLS, models 1-22 1, L-50 1 and 
L-1010, use a portable variable AC-control sys- 
tem operating from a 120-volt AC line. The sys- 
tem enables the user to select and adjust AC 
voltage at any level from to 140 volts to provide 
power for applications up to 10 amperes continu- 
ous duty or to 100 amperes surge. Housed in an 
aluminum enclosure, the units feature fused 




CIRCLE 152 ON FREE INFORMATION CARD 

three-wire grounded circuitry for user safety, an 
on-otf switch, a pilot lamp, and front-panel con- 
trols. Modal L-221 is rated 1.75 amps, L-501 Is 
rated 4.5 amps and L-1010 is rated 10 amps. 
Applications include portable use. lab and bench 
applications, or incorporation into machines and 
equipment. Model L-221 Is $58.00, Model L-501 
is $74.00 and L- 10 Wis $88.00.— Staco Energy 
Products Co., 301 Gaddis Blvd., Dayton, OH 
45403. 

KEYBOARDS, designated Fastype, are a line of 
alphanumeric keyboards featuring a patented 
membrane-switch technology that provides a life 
rating of 50 million operations per key, and a con- 




CIRCLE 153 ON FREE INFORMATION CARD 

tact bounce less than 2 ms. Characterized by low 
EMI emissions, the units run silently with a force 
of 3 to 5 ounces per key and 5 to 7 ounces per 
space bar over a 0.150" travel. 

The keyboards come in a variety of models with 
various key-cap styles and widths, special colors 
and legends. Backer boards come in either phe- 
nolic, metal or PCB. Flextafl terminations are 
standard; other terminations can also be provid- 
ed. Price is typically $30.00 each in OEM quanti- 
ties. — Chomerics, Inc., 77 Dragon Ct., Woburn, 
MA 01888. 

ELECTRONIC THERMOMETER, No. 71,741, Is 
designed for temperature readings at various 
locations both indoors and outdoors. This bat- 
tery-operated thermometer has three sensors 
which allow the user to measure and monitor 
temperatures at three different locations as far 
away as 1,000 feet. 




CIRCLE 154 ON FREE INFORMATION CARD 

Operated by pushbutton, the unit gives read- 
ings from minus 22 s to plus 122° Fahrenheit, or 
from minus 30° to plus 50° Celsius with accuracy 
of one degree. It is finished In a walnut-grained 
cabinet and comes with three waterproof temper- 
ature probes with 15-foot cables. Price is $87.00 
plus $3.50 for packing and delivery.— Edmund 
Scientific Co., 7082 Edscorp Bldg., Barrington, 
NJ 08007. 



TEST UP TO 

100 WATTS/STEREO 

200 WATTS/MONO 



it 



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Now test an amplifier or receiver's maximum 
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loads (which are MIL grade non-inductive), or to 
the external speakers. 

To order, or for more Infoimation, contact 



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CIRCLE 3 ON FREE INFORMATION CARD 



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How two or more radios can share the same antenna in 
simple peace and harmony. 

HERB FRIEDMAN, COMMUNICATIONS EDITOR 



EVERYONE KNOWS SOME PERSON WHO IS 

always working for a "good cause." If 
it's not raising money for starving 
children on the other end of the earth, 
it's getting a sponsor for a Little League 
team, or blood donors for a hemophiliac. 

The problem is that these people are 
really sincere, and it's almost impos- 
sible to refuse them when they appear 
at the door. Our neighborhood "do 
gooder" recently showed up with a 
stack of VHF receivers he had collected 
so that guests in the local Retirement 
Home could listen in to police, fire, 
emergency calls and the radio-telephone 
service. Naturally, I couldn't refuse his 
request to "get them working," though 
even Heaven couldn't get some of them 
to stop drifting long enough to receive 
a complete thought. 

One of the interesting aspects of that 
motley assortment of VHF/UHF re- 
ceivers was that almost all of them used 
separate antenna inputs for VHF and 
UHF. and some even had separate 
VHF-low and VHF-high antenna con- 
nections. Perhaps that was excusable 
back in the good old days — whatever 
they may be — but after the introduction 
of the CB/BC (citizens band and broad- 
cast band) antenna-splitter in the early 
1960's, there was never a valid reason 
for separate antennas and multiple an- 
tenna inputs on consumer equipment. 
Today, of course, VHF/UHF gear uses 
but one antenna input for two, and 
sometimes three, individual front ends 
without interaction — that is, without 
one front end shorting the signal meant 
for another front end. 

To understand how one antenna input 
is used for two or more front ends, we 
need only look at a CB/BC antenna 
splitter, for it is the least complex in 
terms of design, and also the most easily 
understood. 

Figure I shows two versions of the 
same CB/BC splitter. Figure l-a shows 
the original low-loss design, while Fig. 
l-b shows the final commercial version 
using a low-cost resistor in place of the 
relatively expensive radio-frequency 
choke, RFC I. Except in rare instances, 
the additional loss created by the resis- 
tor went unnoticed, hence. Fig. l-b be- 
came the standard commercial version. 



CB 

TRANSCEIVER 



5DnCB ANTENNA 
ALSO SERVING 
AS AN 

AUTO RADIO 
ANTENNA 



V 



L1 



CI 
20pF 



X r =5KAT 
1.6 MHz 



RFCl 



AUTO 

RADIO 



Z=3S2AT1.6MHi 

AND500fiAT27MHz 



CB 
TRANSCEIVER 



50HCB ANTENNA 
ALSO SERVING 
AS AN 

AUTO RADIO 
ANTENNA 



V 



LI 



C1 
20 pF 



AUTO 

ha mo 



R! 

soon 



FIG, 1 

The splitter operates on the principle 
that when two resistors or impedances 
are in parallel, and one is I0 times the 
value of the other, there is virtually no 
effect on the working circuit by the 
higher resistor. The inverse is true in 
series circuits. (I am certain that many 
readers can document numerous ex- 
ceptions to that rule.) 

In Figure l-a, LI and CI form a 
series -re son ant circuit tuned to 27 MHz. 
Capacitor CI has a reactance of 5000 
ohms at 1. 6 MHz, a frequency repre- 
senting the top of the broadcast band. 

RF Choke RFC I has an impedance 
of 500 ohms at 27 MHz, and 3 ohms at 
1 .6 MHz. The antenna system is a dual- 
band automotive radio antenna. It acts 
as a standard antenna at AM broadcast 
frequencies (0.550- 1. 6 MHz) and pro- 
vides a 50-ohm load at 27 MHz. 

When the CB transmitter is keyed, 
the RF output "sees" a low-impedance 
path through the series-resonant LI— 
CI network to the 50-ohm antenna 
load. In parallel with the 50-ohm an- 
tenna load, the CB transmitter sees the 
500-ohm impedance of RFC I, so vir- 
tually al! the RF flows to the antenna. A 
received 27-MHz signal sees the low- 



impedance path through L I — C I to the 
CB, with a parallel load of RFCl, so 
almost all the received signal goes to 
the CB. 

When a broadcast-band signal is re- 
ceived, the signal from the antenna sees 
a 3 -ohm path through RFC I to the 
broadcast radio, and a series path to the 
CB of at least 5000 ohms through the 
impedance of LI and CI: hence, essen- 
tially all of the received AM broadcast 
signal goes to the broadcast band radio. 

In actual practice, LI — C I is tuneable, 
and is user-adjusted for minimum SWR 
at the CB transmitter output. 

Everyone always likes to come out 
with a less expensive model than his 
competitor; there's little that can be 
eliminated from the circuit other than 
substituting a resistor for RFCl. and 
that's just what was done in many CB 
splitters. Figure l-b shows the "budget" 
model. The theory remains the same 
except we now have a fixed impedance 
for RFCl. Now the broadcast signal 
from the antenna must flow through 500 
ohms to the receiver, rather than 3 
ohms maximum. Is there a loss? You 
betcha. But the radio's AGC can often 
compensate for the loss. Only extremely 
weak signals — usually too weak to acti- 
vate the AGC — wit! be lost because of 
Rl. 

Another reason for the switch from 
an inductor to a resistor for RFC! was 
the sudden popularity of AM/FM auto- 
motive radios. If RFCl could block a 
CB signal at 27 MHz. it sure as heck 
could block an 88- 1 08 MHz FM signal. 
Resistor Rl. on the other hand, will 
pass the FM frequencies, though there 
will be a loss of some 2! dB, not an in- 
significant value when tt comes to FM, 
A moderate signal can simply disappear 
into the noise level or the signal might 
be reduced below the receiver's stereo 
threshold. 

That type of splitting, whereby one 
antenna is used for two or more inputs, 
outputs, front ends, or what have you, 
at the same time, is called multiplexing. 
Now let's look at how one antenna is 
multiplexed in a modern VHF-UHF 
scanner. 

Figure 2 is a simplified diagram of the 
antenna/front end of Radio Shack's 
latest programmable scanner, the PRO- 
2008. It has separate front ends for 
VHF-low (30-50 MHz), VHF-high (144- 
174 MHz), and UHF (4I0-512 MHz). 
continued on page 122 



116 




Designing 
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digital electronics. 

Contents include: Binary, octal and 
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NEW IDEAS 

continued from page 110 



end of the tube into the hole, again being 
careful not to get cement inside the tub- 
ing. Allow sufficient time for the cement 
to dry before handling the air pipe fur- 
ther. The completed air pipe should look 
like the one illustrated in Fig, 4. Finally, 
cut a piece of plastic canvas to fit on top 
of the air-pipe assembly and cement it in 
place. The canvas provides a level resting 
surface for all PC-board sizes, and its 
open grid allows the air bubbles to flow 
easily to the surface. 

To use the etcher, place the air pipe 
and board to be etched in the case, con- 
nect the air pump and air pipe with a 
piece of the '/i-in. ID flexible tubing, and 
fill the case with enough etchant solution 
to cover the top of the board. Then, plug 
in the air pump and watch the resulting 
action. — David L. Holmes 



COMMUNICATIONS CORNER 

continued from page 116 

Inductor Li's reactance, while low 
enough to pass 30— 50-MHz signals, is 
sufficiently high to block VHF-high and 
UHF signals from being shorted to 
ground by Tl's primary (antenna) 
winding. Only VHF-low signals enter 
Tl, where they are passed into the 
VHF-low tuner. 

VHF-high signals enter their tuner 
through L2 and C21. Inductor L2's 
reactance is high enough to block UHF 
signals from T4. Capacitor C2l's re- 
actance is high enough to block VHF- 
lo signals. 

UHF signals are passed through C32 
to the "top" of L3. Capacitor C32's 
reactance is sufficiently high to block 
both VHF-high and VHF-low without 
seriously affecting UHF reception. 

On paper, that can look complex at 
first glance, but as you can see it's not 
much different from the basic CB 
splitter shown in Fig. 1-a. 

Now think. If it's really that easy, 
was there any valid reason why some 
late-model solid-state "scanners" re- 
quired more than one antenna input? 
(Again, I expect a stack of letters on 
why multiple antennas are better.) 

By the way, if you have any old scan- 
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are some, they are certain to be ap- 
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All new! 

All construction projects! 



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Car Test Probe — 
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Adventures of the 
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Communications 
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123 



Excessive brightness and the circuit faults that can cause it. 

JACK DARR, SERVICE EDITOR 



IN THE DECEMBER 1979 COLUMN WE DIS- 

cussed raster-cutoff problems and their 
causes. Now we take up the equal but 
opposite reaction, where the screen flares 
up and the brightness control won't turn 
it down. In mild cases, the raster will be 
too bright, the colors pale, and vertical 
retrace lines may show up. (It's a good 
idea to check the setting and range of the 
AGC control before anything else; that 
can cause it, too.) In the worst cases, the 
raster will be far too bright, colors will 
bloom and there will be a loss of focus. 

The basic cause will be the same as 
before. Something is upsetting the bias 
on the picture tube so that it is conduct- 
ing far too heavily, ft cannot be cut off 
with the controls. Let's look at some real 
cases. 

One common cause is setting the 
screen controls too high. Since that con- 
trols the cutoff point of the pix tube, the 
controls must be set correctly. My pet 
method is recommended by several set 
makers. Set the service switch to the 
SERVICE position and then turn all screen 
controls ail the way down. Bring one 
screen control up until a line is barely 
visible, then turn it back until the line just 
disappears. Do that with the other two 



v*v 



SCREEN controls and they'll be very close 
to the correct setting. 

You can get boobytrapped on this! I 
once was. Got the set from another shop. 
The complaint was "Raster but no vid- 
eo." Right. Checked for video signal and 
found it on the grid of the video output 
tube; none at all on the plate. There was 
no plate voltage on the tube, either. 

Normally, that should have put the ras- 
ter out due to raising the cathode voltage. 
Yet, I could see a raster! Frankly, 1 forgot 
one thing and spent a bit too much time 
before it hit me. The last guy who worked 
on it hadn't found the missing plate volt- 
age but he had cranked all three screen 
controls wide open! That raised the cutoff 
point of the- tube to the point where even 
the high cathode voltages couldn't bias it 
off. Replacing the open resistor and reset- 
ting the screen controls fixed it up. 

In the older sets, the cathodes of the 
three color-amplifier tubes were all tied 
together and Fed by the black-and-white 
video signal. The three control grids were 
each fed by one of the color signals. 
Those came from the three color-differ- 
ence amplifiers. The red and blue signals 
are amplified here and the green signal is 
developed by matrixing (mixing) the red 



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and blue signals in a common cathode 
resistor. Figure I shows that circuit as 
found in many sets. Older sets used a twin 
triode and one triode section of another 
tube. Later sets used a special triple- 
triode, but the circuits were identical. 

The plate voltages of those tubes con- 
trolled the DC voltages and signals on 
their respective color grids in the picture 
tube. So, what happens if you see a one- 
color problem? Too much red or not 
enough red, etc.? You have a fault in the 
stage that amplifies that color only. What 
happens if you have a fault in something 
that affects ail three at once? You have an 
upset of all three grid voltages on the pic- 
ture tube, and in most cases, the grid volt- 
ages go too far positive and the raster 
flares and gets far too bright! 

In one case, an RCA CTC-25, the ras- 
ter flared. With the service switch in the 
service position, the setup lines were at 
least an inch wide and so bright we didn't 
dare leave the set on for more than a few 
seconds for fear of burning the screen! 
We hunted around and finally solved the 
problem. We happened to look at the top 
or the chassis. Both of the diffamp tubes 
(6GU7) were dead! Checking the pic- 
ture-tube grid voltages we found the full 
+ 350-volt DC potential from the supply 
on each one. Without a heater in the 
tubes, they drew no plate current at all. 

The cause of that was a bad solder joint 
in a wire jumper on the PC board, in the 
6GU7's heater circuit. In another RCA 
chassis with similar symptoms, the differ- 
ence-amplifier tubes were good. The bad 
solder joint this time was at one end of 
the common cathode resistor. This time, 
we used the method I've been recom- 
mending and found the cause far faster 
than we had in the first case. I have 
said — and I say again — always check the 
DC voltages on the picture tube! 

Since the bias voltage on a picture tube 
is always the difference between the cath- 
ode and grid voltages anything that hap- 
pens to either one can change it Grids 
can go positive or the cathode can go too 
far negative. I remember one set with a 
flaring raster and blooming. A check 
showed the cathode voltages to be almost 
zero. Since grids were still at +200 volts, 
that left them with a high positive bias. 
That was due to an open video peaking 
coil between the video output tube plate 
and the picture tube cathodes. The high 
B+ voltage to the cathodes was fed 
through this coil. 

Some of the early sets use a sort of 



elementary brightness-limiter circuit. 
Thai is ■ usually called a brightness 
range control, and is simply a pot in 
series with the main brightness control. 
To set this up correctly, the main bright- 
ness control is turned all the way up and 
the brightness range control set so that 
the picture is just below the point of 
blooming. Some recommend setting for a 
specified DC voltage developed across a 
test-point resistor. If the range control 
isn't set correctly, it can be possible to 
turn the main brightness control to the 
point where the raster will flare or be far 
too bright. Normal symptom of this is 
when the brightness control will not turn 
the raster off. 

To repeat something mentioned re- 
cently: in the later RGB sets with com- 
mon grids, the DC bias -voltage is set by a 
resistance divider. If the ground leg of the 
divider opens, the grids go too far positive 
and the raster is too bright. 

No matter how new or old a TV set is, 
you'll find the same basic relationship 
between the grid, cathode, and screen 
voltages of the picture tube. And the 
'same results, if any of the bias levels go 
off value. So, as I keep saying, develop a 
habit of checking those voltages whenev- 
' er you run into any kind of brightness 
problem. -That can save you one heck of a 
lot of time! R-E 

service 
questions 

SUB FOR 60060 TRANSISTOR 
I've got a WT-509A RCA cathode ray 
tube tester. Wrote to VIZ for an up-to- 
date setup booklet. With it, they sent an 
addendum to the manual, suggesting re- 
placing the 39278 transistor with a 60060. 
Now, I can't find this translator anywhere, 
and no listing of ill Do you know of a 
sub? — R.F., Chicago, IL. 

RCA lists a 60060 (industrial number) 
in their SPG-202X Guide. They say that 
an SK-3054 will replace it. This is a TO- 5 
cased, high voltage type, "with flange". 

AGO BUCKING RESISTOR 
There's an AGC problem in this West- 
inghouae model CP19A770. 1 can't get the 
right voltages. There is a keying pulse on 
the AGC tube, and a small change on the 
plate with or without a signal. The picture 
is too dark, and I can't adjust it. — F.N,, 
Pewaukee, WN. 

Your AGC voltages and reactions seem 
to be OK. Suggestion: There's a 15- 
•megohm resistor in a line from the AGC 
test point over to the B4- 255-volt line. 
Lift one end of this resistor and check it. 
If it is open or has gone way up in value, 
there won't be enough "bucking voltage" 
to keep the AGC from driving itself too 
far negative. This cuts the IF gain, which 
results in a dark picture. This used to be 



quite a common problem some time ago; 
the case you describe is the first I've seen 
for quite a while. 

VOLTAGE-REGULATOR PROBLEMS 

Here's a dandy one in a Panasonic CT- 
914 (ETA- 1 2) chassis. If you get one 
with a vertical flutter in the picture, don't 
concentrate on the vertical circuits! It 
could be caused by the DC power sup- 
ply! 

Capacitor C808, 1 .0 uF, 1 60 volts, may 
be open. That is in the line from the 
bridge-rectifier output to the Trigger- 
Pulse SCR, TR802. Evidently a pulse- 
shaper in an R-C network with R804, 
(56 K) to the gate of TR802. 

If the sets shuts down instantly when 
you put the new capacitor in, yank it out 
and check for leakage! Even a new one 
can be bad. Symptoms of that Mutter: 
+ 1 10-voIt DC supply will be low, about 
+ 107 volts or so, and it will fluctuate. 

Thanks a lot to Douglas P. Hoff of 
Vacaville, CA for that helpful hint. 

TWO PROBLEMS— ONE SET 

I've got a sticky problem in this Zenith 
16Z8C50. The high voltage is up to 31 kV, 
and the high-voltage adjust pot won't 
change it. The brightness control does 
vary brightness and the high voltage. I've 
checked several things in this circuit. No 
luck. I have another odd one. My voltme- 
ter probe slipped while checking the 
damper plate, and hit the cathode. There 
was a loud 'pop', and now I read +500 
volts instead of +390, +310 volts instead 
of +250, and I get + 1036 volts on the 
880V boost. Can you tell me what to 
check from here on?—D.P., Berwyn, IL. 

Yes, First, check your voltmeter and 
make sure it 's OK! That may explain the 
extra 60 volts. (Ask me how I know? I did 
the same thing some years ago in same 
place with same results! Sixty bucks for 
new parts for my meter made me much 
more careful.) 

As for the high-voltage problem, you 
mentioned that the voltage on the 6HV5 
regulator- tube grid is off. That is apt to 
be the cause of your high-voltage prob- 
lem. Check it while turning the high-volt- 
age adjust control; see if it varies as it 
should. If not, check all resistors and 
capacitors in the grid circuit. Those have 
been known to break down under load 
causing the symptoms you mentioned. 

NO REGULATION ON PICTURE 
TUBE 

When I wrote you originally, you told 
me to check the DC voltages on the pic- 
ture tube. (RCA CTC-72 chassis, no 
voltage regulation on picture tube, high- 
voltage way up. I did; the DC voltage on 
the common grids read normal, but there 
was an open connection between the pic- 
ture-tube socket and the pin to the grids! 
Bit of prying fixed this and everything 
works. 

Thanks to R. Jimenez of NJ for the 
feedback. R-E 




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UNICORN 1 

continued from page 95 



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FIG. 25— MOTORCYCLE BATTERY used to 
power robot. Sea text for important mounting 
precaution!. 

used to hold the battery in place and to 
support its weight, since the plates that 
cover the mobility base are probably not 
strong enough to do this by themselves.' 

Certain precautions must be observed 
when using this type of battery! As shown 
in the photograph, the battery is unen- 
closed, which means that there exists the 
possibility of sulphuric acid, the battery's 
electrolyte, spilling on the aluminum or 
steel of the mobility base. You do not 
want this to happen! The battery should 
be (and is, in later versions of the robot) 
enclosed in an acid-proof plastic contain- 
er to contain any possible leaks or drips. 
This container should also have a small 
vent, or vents, at the top to permit the 
hydrogen gas which is generated when 
the battery is charging, to escape. These 
vents should be led to the outside of the 
mobility base, to allow the gas to escape 
directly to the air. 

There is another type of battery which 
might be considered for powering the 
robot. That uses a gelled-electrolyte and 
is, in theory, less hazardous. New batter- 
ies of this type are more expensive than 
lead-acid batteries, but several advertisers 
at the back of Radio-Electronics have sur- 
plus gelled-electrolyte available, and they 
may suit your purpose. 

Whatever power source you use, take 
precautions so that it cannot harm, direct- 
ly or indirectly, the innards of the robot. 

Leads are run from the battery to a 
32-position barrier strip (see Fig. 26) 
which is also mounted inside the mobility 
base. Power for the robot's various mo- 
tors and control circuitry is obtained by 
running jumpers from the +12 VDC and 
ground terminals to those connected to 
the points to be powered. Note the use of 
color-coding in order to make circuit 
tracing easier. 

Several terminals have been allocated 
for functions that have not yet been dis- 
cussed. Don't worry — we'll get to them. 

In the next installment of this series, 
plans for the robot's body will be given, 
along with an option or two previously 
hinted at. R-E 



NEW LIT 

continued from page 114 



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"ACTIVE IS AGGRESSIVE" 



LM301AH-8 

LM304CH 

UUTN « 

Lxweft 8 

LM308CH 
LU309K 
UJ310HC 
LM311N-8 
LM317T 
fTOHQI 
LM3H3H-8 
V . LM318CH 



UNEAR I 

.34 LM324N 
LM339N 
LM34BH-H 

LM35SN-B 
LM555N-8 
LM556N-14 

i vraoi 

lU.':\Mf,-l.'. 
LM725CM-0 
LM733CN-14 
LM739CN-1 4 
LM741CH 



89 
.25 
.55 
55 
1.39 
1.45 
.55 
1.15 



C.'s 



.89 

.40 

1.75 
t.Sl 
1.20 
.65 



LM741CN-B 


N 


LM747CN-14 


n 


LM748CH-8 


M 


■.'.'.14551. g 


M 


LM14SSI-14 


M 


UJ14B0N.14 


M 


Lr.'3rj4£t, ■: 


pf 


LA13302N-14 


a 


LM3403N-14 


m 


LM3900N 


a 


LM4136NT4 


45 


ULN2D03AN 


M 



nj 



DUAL-IN-LINE — LOW PROFILE — IC. SOCKETS 



CONTACTS 


PRICE 


8 PIN 


»7 


14 PIN 


.11 


IS PIN 


.13 


18 PIN 


.17 


20 PIN 


,19 



CONTACTS 


PRICE 


22 PIN 


2\ 


24 PIN 


.23 


28 PIN 
10 PIN 


.27 


.39 



. LOWEST PRICES ANVWHEHE FOR THE HIGH 
UNBEATABLE COMBINATION 



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CMOS 










PLASTIC POWER ^ 
TRANSISTORS 


CO4O00BE 


JO 


C 04021 BE 


.74 


CO4046BE 


.89 


CO40B2BF. 


.23 


CD4527BE 


1.47 


CD4001BE 


.39 


CO4022BE 


1.10 


CD4047BE 


.B4 


CO40S5BE 


.82 


CDJ528BE 


J4 








CD40O2SE 


.23 


C04023BE 


J7 


CD40W8E 


54 


CO408SBE 


.79 


;..dj-:ii=f 


.S9 


TIP30 


:m 




CD40O6BE 


1.19 


CD4024BE 


.52 


CD4O50BE 


.44 


CO40938E 


SI 


CD4532BE 


MS 


TIP3J 




NPN 3AV.P1MV 


CM007BE 


.39 


CO4025SE 


.20 


CD4051BE 


.82 


CD-B99BE 


1.98 


CD4539BE 


.84 


■TIP32 


■S3 




CD4008BE 


.84 


CO40MBE 


1.70 


GD4052BE 


1.19 


CD4104BE 


1.99 


C04543BE 


1.49 




CDJ009BE 


,S4 


CD-:S275= 


.49 


CD40S3BE 


1.19 


CD4509BE 


1.89 


CD45538E 


2.98 








GD4U10BE 


.59 


CD402SBE 


57 


CD4060BE 


1.99 


CD4510BE 


.84 


CD4S5SBE 


.74 


' TIP42 


fi4 


PNP 6AMP1IMV 


CD40118E 


.34 


CD4029BE 


.04 


CD406SBE 


.99 


CD4511BE 


,74 


CD4556BE 


.89 








CD4012BE 


.29 


CD4D30BE 


.45 


CD4068BE 


.29 


C04512BE 


.88 


CD4581BE 


1.99 








CD4013BE 


.49 


CD.1S.K3F 


1.79 


C 04069 BE 


.27 


CD4514BE 


2.35 


CD4582BE 


.88 








CD4014BE 


.89 


CD4034BE 


2.70 


CD407QBE 


.30 


CD4515BE 


2.10 


CD45B4BE 


.54 


TIP122 


P 74 


NPN SAMP 100V 


CD40158E 


.78 


CO403SBE 


1.14 


CD4072BE 


.23 


CD451 BBB 


1.39 


CD45B5BE 


99 








CD4016BE 


14 


CD4040BE 


.99 


CD4073BE 


39 


CD4518BE 


.80 


CD1S,S:J!SE 


8.89 








CD4017BE 


.72 


BO4011BE 


1.56 


CD4075BE 


M 


CDJ519BE 


jg 


CD4702BE 


1.19 








CD4Q18BE 


.19 


C0404ZBE 


.B7 


CD407SBE 


.B4 


CC4520BE 


.77 






TIP295S 


M 


PNP 15 AMP 60V 


CC4019BE 


1.25 


CD4043BE 


.99 


CD4078BE 


M 


CD4523BE 


.93 












1 CD4020BE 


.99 


CD4044BE 


.79 


CD40S1BE 


ZT 


CD452SBE 


.99 




\ 


FT30S5 


Vj 


NPhMOAMP l50Vj 



OPTO SALE 

LE.D. LAMPS 
LED209 T-1 2 mm Rod 
LED31 1 T-1 3 mm Gn on 

LED212 T-1 SmmYclIci* 



LEO320 T-1 V< 5 mm Bo<1 

LED223 T-1V.5 mm QtMn 
LE D324 T-1 =i S mm Vshow 



375" 



FND357 
FND500 500- 
FNO507 500' 
DL704 .300 
□L707 .300/ 
OL747 .630 
DL1416 
4 digll„16 



ILD74 
ILQ74 

ILCTB 
TIL111 
4N2S 
4N33 



DISPLAYS 

Common CathodB 
Common Caihwje 
Common An«i« 
Common OiUnoOO 
Common Anod* 
Common Annd* 



M 



.99 

1.20 
1.39 
2-28 
20.95 

AJpnanumanc display 16 til 



ISOLATORS 

Dual Opto Isolatot 
Quad Opto Isolator 
Dual Opto Isolator 
Oplo Coupfcjr 
Oplo Isolator 
Opto trulator 



15O0V 
1500V 
150GY 

tKJOV 
2SO0V 
1S00V 



1.29 
3.09 
1.29 
M 



TTL 

74LaOCN 
74LS01N 

74LS03N 
74LS03W 
74LS04N 
74LS05N 
74LSOSN 
74LS09N 
74LS10N 
741.S1 IN 
74LStiN 
74LS13N 

V-t.si.--. 



ALL CIRCUITS IN STOCK FOB GUARANTEED IMMEDIATE OELIVERT. 



-25 
.22 
JT 
.7! 
.29 
.25 
.27 
.25 
.27 
.39 
.22 

.;•:■ 

.55 



74LS20N 
74LS21N 
74LS26N 
74LS27N 
74L530N 
74LS33N 
,' 1! S3SN 
74LS40N 
74LS42N 
74LS47N 
74LS4SN 
74LS51N 
74LS54N 



,27 
,56 
.32 
.2* 



74LS55N 
74LS73N 
71LS74N 
74LS75N 
74LS75N 
74LS78N 

741 BS3M 
74LSB5N 
74LS8SN 
741.S90N 
74LS91N 

-1lS5-«, 
74LS93N 



74LS95N .89 

74LSOBN .78 

74LS107N .48 

74LS109N .49 

74LS112W ,4S 

74LSt32N .541 

74LS123N ,88 

74LS124N .95 

74LS125N 15« 

74LS136N .94 

74LS132N .48 

74LS133N 2.88 

74LS136N .68 



74LS137N 
74LS13BN 
74LS139N 
74LSI45N 
74LS147N 
74LS14BN 
74LS1S1N 
74LS153N 
•ii S165N 
?4LS156N 
74LS157N 
74LS15BN 
74LS160N 



79 
.73 
1.25 

::.5S 

2.25 
.5-1 
.15 



.78 

1.20 



74 LSI SIN 1.29 
71LS1S3N tJ9 
74LS163N 1^9 
74LSt64N .98 
74LS1BSN 1.4S 
74 LS ISSN 3.54 
74LS1ESN B.73 
74LS170N 2.78 
74LS173N .78 
74LS174N -54 
74LS175N .54 
74LS181N ISt 
74LS1S0N 1J» 



74LS191N 1^9 
74LS192N .78 
74LB193N 1,39 
74'.. 51 0.1 N 1.89 
74LS19SN .89 
74LS196N 1JI7 
74LS107N M 
74LS221N 1.15 
74LS340N 1J» 
74LS241N 1.18 
74LS242N 1.18 
7JLS243N 1.19 
74LS244N 139 



74LS2J5N 3.10 

74LS247N .89 

74LS248N 1^4 

74LS249N ,99 

74LS251N 1JB 

74LS353N .79 

74LS257N .09 

74LS25BN .84 

74LS259N 3.0B 

74LS260N .98 

T4LS26BN .59 

74LS273N 1J2 

74LS275N 6.03 



74LS279N .79 
74LS2BON 3.55 
74LS2S3N .95 
74LS2S0N ^9 
74LS293N .» 
74LS295N 13R 
74LS298N 1J» 
74LS2B9N 3.80 
74LS320N 4.95 
74LS321N 4.95 
74LS322N 4.95 
74LS333N 4.95 
74LS33JN 1j*7 



74LS348N 2.9S 

74LS353N 1JS 

74LS3S3N 1JT 
74LS3S2N 11. 0« 

74LS3065N 2J8 

74LS366N 1.20 

74LS367N 1^4 

74L&36BN 1^4 

J4LS373N 1.94 

74LS374N 1.84 

74LS375N 2JH 

74LS377N 1^44 

T4LS37BN 1,69 



74LS379N 2-20 
74LS390N 2J4 
74LS393N 245 
74LS3B5N 1.95 
74LS447N .37 
74LS400N 2.45 
74LS630N 1 10.00 
74LS631N 110,00 
7JLS660N 2JS 
74LSS70N 3.65 



MICROPROCESSOR 
CHIP SETS 



Part Ho. 


Prtca 


sosoa 


55.6b 


8085 


11.9$ 


8212 


2.75 


8214 


3.95 


8216 


Z05 


8224 


345 


B226 


2.95 


8328 


4.9B 


8238 


4.95 


9251 


695 


8253 


10.95 


8255 


B.9S 


8257 


10.95 


8259 


12.98 



Prjrl No- Prlc. 
SS00 55.59 

BB02 11.98 



5810 
6820 

SB21 
6850 
8592 



3-7S 
4.95 

3.TI 
3.95 
3.7S 



IH 

Pan No. 


PrlM 




6502 


59.95 




6504 


9.05 




6506 


9-95 




6520 


8.9S 




6522 


9.95 




S532 


13-95 




6551 


13.95J 





( SCR's and TRIAC's 



0106Q 

TIC 11 SB 

TIC126B 

T1C216B 

TIC226D 

TIC236D 

TIC 2460 



J4 

.97 
1.00 
.00 
.95 
1.45 
1.45 



SCR 5 amp 400V TO-220 
SCR 9 amp 200V TO-220 
SCR 12 amp 2O0V TO-220 

Triac 6 amp 3D0V TO-220 
T/inc 6 amp 4O0V TQ-220 
Trlac 12 amp 400V. TO-220 
Tnac 18 amp 4O0V TO -320 



Bi-Fet OP AMPS 



TL-054CN 2.75 Quad low powur TLOS1CP .4 9" J-FET inoill 
TL071CP .59 LownoiM TLOS2CP -99 Dual J-FET mput 
TL072CP 1.19 Dual tow rOiM TL064CN 1,95 Quad J-FET aiput 
i.-'< low ma j 



BONUS!! 



■ i_u- iL'wr ;i, 19 UlaaV mj 

\ TL074CN 2.3S Quad L 



RETURN THIS AC WITH YOUR ORDER 

AND RECEIVE FREE SAMPLE — 

ONE DOUBLE SIDEO COPPER 

PRINTED CIRCUIT BOARD. 



I 
I 
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16K MOS DYNAMIC HAM'S (16 PIN) 
416-3 (300ns) Ceramic 5.95 

4. 1 6-5 (300N S) Coram fc 4.S5 

4K MOS DYNAMIC RAM'S 
TMS406O-30 Special 2.95 

4K (4Kk 1J300NSB2 PIN 
TMS40SO-Z0 3.9S 

4K (4Kx 1)200NB2J PIN 



"Memory Specials? 

EPROM'S 

CZ708 

IK x 8 450 ns 
TMSSS32 

32K I-S09S x 8) 450 ns 
TMS2716 

16K(2Kx8)4S0ns 
(3 fjowor supplies) T.I. Version 
C2716/TMS25-I6 
16K (2K X 8) 450 ns 

(Single 5V supply — Similar to umoi version) 
TMS2564 
^MKjSK^ 8) fJ0jis_ _ 



•I 




5 69.35 
S 13.35 



$ 14.S5 



$395.00 



MOS MEMORIES 

MPS Sialic RAM's 
Pan No. 
2102-29 

IK ;K » II 250NS 16 PIN 
P21 11-35 

IK ,;256 « .;;, 350NS 18 PIN 
P21 12-35 

IK (2SBX4I350NS 16 PIN 
2114L 

Low Powor 4K (1024 t 4) 300NS 
2147 

4K I4K X 1 ) 55N5 
3147 
4K (4K > 1 ) 70NS 

UARTs 
AY5-1013A 

10 40K BAUD 40 PIN 
COHKrtT 



-> 



Prlca 
1.W 

3.95 

3.45 

6.95 

10.95 

14.95 



43 Ktu Stnglo 5V SoppN 

1KCMOS RAM 
5101 

1 K [256 X 4) 450NS 22 PIN Low Powar 
4K CMOS HAM 
P6504 

4K (4K X 1) 550NS 16 PIN 110MW 
P8S14 
4K (IK X 41 450NS 18 PIN 1 10MW 

SHI FT qEGiSTER S 
3341APC FIFO :T7Hi 
3342PC 64 Brl Shift Ragkalw 
3347PC 50 Bil StiJft RsgiilBr 

ECL RAM 
10410ADC/HM2106 
256 X 1 Bil Fully Dacodod 15NS 16 PIN 



3.95 

Special 3.95 



12.95 
15.95 



4.45 
3.95 



Special t.os 



IN CANADA VISPT OUR NEW CALGARY LOCATION 



P.O. BOX 1035 FRAMINGHAM. MASSACHUSETTS 01701 



Owi'l-tle courtier 1.1 
17 Mr<ccr Hd U.H i 
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TelepFiGJir- ijnSi-i - .-. 



M&i KERHIEIS1 
MONTREAL OUElWt 



OAXtl I. CEHTHI 

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M.hlWllM ORDER ^10 00 > ADD S3 00 TO 
COVER POSTAGE & NANQLItiG 



!ti(HJ DUJ-FLRIN ^E -Hit'i M.u | Mill IIIAII 

DOlrVFMSVIEW. ONTARIO UNI I 103 
M3H 5S9 I *l OAI»V M 0\ HI* 

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,. I ' ■ ,'L .1 N 1 1 

MASTER CHARGE 
ACCEPTED 


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mill KiNliSWAT 

VANCOUVER in: 

v-.ll 5J7 

ItH (6041 1 »t l.i,' ■ i 


m 

03 
O 



CIRCLE 64 ON FREE INFORMATION CARD 



129 



BUSINESS OPPORTUNITIES 

MECHANICALLY Inclined Individuals desiring 
ownership of Small Electronics Manufacturing 
Business— without Investment .Write; BUSINESS- 
ES, 92-R. Brighton 11th, Brooklyn, NY 11235 

PROJECTION TV . . . Make $200.00+ per eve- 
ning assembling projectors . , . Easy . . . Re- 
sults equal to $2,500 projectors . . . Your total 
cost less than $15,00 . . . Plans, lens & dealer's 
Information $14.00 . . . Illustrated information 
free . . . MACBOCOMGBX, Washington Cross- 
ing, PA 1S977 

$700 per month earnings possible filling out 
income tax forms at home or tax office during tax 
season. We show you how. Simple, quickly 
learned. Details mailed free. No salesmen. Hurry. 
Big demand. FEDERATED TAX, 2015 Montrose, 
Chicago, IL 60618 



FOR SALE 

SCANNER/monitor accessories — kits and facto- 
ry assembled. Free catalog. CAPRI ELECTRON- 
ICS, Route 1R, Canon, GA 30520 

FREE catalog, IC's, semi's, parts. CORONET 
ELECTRONICS, 649A Notre Dame W„ Montreal, 
Que., Canada H3C 1H8. U.S. Inquiries. 

RECONDITIONED test equipment. $1.00 for cat- 
alog. JAMES WALTER TEST EQUIPMENT, 2697 
Nickel, San Pablo, CA 94806 

SAVE up to 50% on name brand test equipment. 
Free catalog and price list. SALEN ELECTRON- 
ICS, Box 82-M, Skokie, IL 60077 

GOVERNMENT surplus receivers, transmitters, 
snooperscopes, parts, fantastic 72 page catalog 
254. MESHNA, Nahant, Mass. 01908 

CABLE TV converters $39.95. Incredible 96-page 
catalog free. ETCO, Box 762, Pittsburgh, NY 
12901 



GIANT communications guide. Info thru 1980. 
Worldwide LW- AM- FM- SW- RTTY- CW- Fax- 
satellite- VOLMET- marine- NOAA- QSL'S- etc. 
$20 00 ppd. GCG, 11625 W. McKlnley, Fresno, 
CA 93711 

OSCILLOSCOPE, DC to 22 MHz, dual trace, 
Navy equivalent to HP170, $199. HAMMOND, 
1013 Lafayette Avenue, Colonial Heights, VA 
23834 

RECORDS-tapesI Discounts to 73%; ail labels; no 
purchase obligations; newsletter; discount divi- 
dend certificates; 100% guarantees. Free details. 
DISCOUNT MUSIC CLUB, 650 Main Street. 
Dept. 3-1060, New Rochelle, NY 10801 

BUILDING a robot? Using stepper motors? Write 
for details. SASE please: SPARKY ELECTRONIC 
SYSTEMS, 95-28 42nd Avenue, Elmhurst, NY 
11374 



AMAZING ELECTRONIC PROJECTS end PRODUCTS; 
Lasers Super Powered, Burning Cutting, Rifle. Pistol. 
Packet. See in Dark— Shotgun Directional Mike — 
Unscrambles — Giant Tesla— Slunwand— TV Disrupt- 
er — Energy Producing, Surveillance, Detection, Elec- 
trifying, Ultrasonic, CB. Auto ana" Mich, Devices, Hun- 
dreds More— All New Plus INFO UNLTD PARTS SER- 
VICE. Catalog St. Information Unlimited, Dopl. R8 Box 
716 Amherst", N.H. 03031. 



QUALITY stock and custom control panels and 
switch plates for computers, industry, home or 
auto. Free flyer. CUSTOM CONTROLS, 4 Fern- 
andes Drive. So. Hadlay, MA 01075 

SURPLUS computer power supplies, test equip- 
ment, parts. Free flyer. UNIVERSAL AUDIO, Box 
712, Providence, Rl 02901 

CAPACITOR kits: Direct from factory beats dis- 
tributor costs. Aluminum, tantalum. Send $3.00 
tor info and 3 samples. STEELE INC, Box 422, 
McKenzie, TN 38201 




r;a 30 channel 

CABLE TV 
CONVERTER 



IGE3S53 HOUTE9N 

I PLATTSBURGH, N.Y. 12901 
I Tit.: IS1SI 5S1-B7M. 




MICROWAVE yagl antenna for MDS complete 
with hardware, type N connector $49.95. SIGNAL 
ELECTRONICS, 4027 18th Avenue, Brooklyn, NY 
11218 

SATELLITE television Information— build or buy 
your own earth station $3.00 U.S.— SATELLITE 
TELEVISION, R.D. 3, Oxford, NY 13830 

RF spectrum analyzer. ASL model 8622, 10 to 
1,000 MHz, 3-inch CRT, manual and application 
notes, weight 22 lbs. Excellent condition. $895. 
M.W. ROBERTS, 3694 East Tompkins, Las Ve- 
gas, Nevada 89121. 702-451-3517. 

TELEVISION downconverters 1.6-2.7 GHz 
$99.95 assembled. Details for stamp. GW ELEC- 
TRONICS, POB 688, Greenwood, IN 46142 

LASER handbook with burning, cutting, Ruby 
Reds, Go's, complete plans, books, and parts. 
Send $4.00 to FAMCO, dept re. box 1902. 
Rochester, NH 03867 

TELEPHONES, answering machines, dialers, 
speakerphones, accessories. Write: CONSUM- 
ERS' TELEPHONE, 69-A Smith St., Glen Head, 
NY 11545 

SUPREME diagram manuals, radio-television, 14 
volumes, special only $25.00. BEITMAN, 1760 
Balsam, Highland Park, IL 60035. 

SME tonearm $79.00; Dynakit mark 111 amps (2) 
$280.00 new & sealed. RAIBLE, 1726 Bentley, 
Los Angeles. CA 90025 



W 
O 
2 
O 
n 

UJ 



O 
o 



CONCORD 

com PUT ER 

componciTtt 

1971 SOUTH STATE COLLEGE ANAHEIM, CA. 92806 

vis» hssthi cnmige /•#■ rtavf ii£<n •nmmuMOUDtR siodo 

IHfOOVMU Ul4/3i/-UbJf SDDilhOtOfllBr 

HD COD ** %ii«j»iI wlHh(i|)BMi,pmir,(miu«( U ci(n CM. MS (DD V, 



74 LS Series 



CPU CRYSTALS 

Fraq Appttatiwi atka 
100 Mfl! 6SOO S4.SO 

1M12 MCM4I1 4LSO 

GSfTVams 4.SO 
TV ana 2.X) 

34?Q2lmtd 5.60 
40041*040 4.50 
BOSS 5GO 

misc.CPV's 4.5Q 
Com SOTS 
ntrjcrWU'i 



I ZOO 
I 20! 
\Z4B* 

4.00 

4.194304 

5,00 

5-OSsa 
10.0 

o.o 
14.3ms 

1S.0 
22.H84 

zm s.go 

an • 5.so 

32.TSB MSM5&32 *3.S5 



*SO 
4.50 
4.50 
4.SO 

BOBOmooa sso 

SOSOA 6.50 



TRS-80 

lGKMemoryAddOn 

tJAK 

WV KIT 

* ith jumpers and 
instructions 




EPROM'S 

2708 . . ■ $6.75 
IK* 8 450NS 

8 FOR $48.50 
2716 - -S12.9S 
i6K(2K*8)450NS 
8 FOR $142.95 

2732 . .***><» 

3 2K (4096*8) 



74L500 

74LS02 

74LS03 

74LS04 

74LS08 

74LS09 

74LS10 

741.S20 

74LS21 

74LS22 

74LS2G 

74LS27 

74LS30 

74LS32 

74LS3S 

74LS42 

I74LS4B 

74LS51 

74LS54 

74LS74 

74LS75 

74LS83 

74LS85 

74LSSB 

74L590 

74LSS3 

74LS107 

74LS112 

74LS113 

74LS122 

74LS123 

74LS126 

74LS1 38 

74LS151 

74LS153 



74LS15S 
74LS158 
74LS1S0 
74LS1S1 
74LS162 
74LS163 
74LS164 
74LS1B5 
74LS170 
74LS174 
74LS175 
74LS190 
74LS193 
74L3195 
MLS 190 
74LS221 
74LS240 
74LS241 
74LS243 
74LS244 
74LS24S 
74LS253 
74LS257 
74LS258 
74LS259 
74LS279 
74LS283 
74L5293 
74LS29S 
74LS366 
74LS3S7 
74 L 5398 
74LS373 
74LS374 
74LS3S6 



i/idea 



i i 



TECHWOLOQY, ll\JC. 




, --.■LNKXXXlittQrtill 
on CRT and kcyboamf. 
AltBtscunCQaditianvliy 
w.wrvn!*xi forovor. 



IQ12D^gQQ 00 





\y 



H2 Z BLACK& WHITE 
LOW COST VIDEO 
MONITOR 





APPLE II Computer 
with full 48K of memory! 



$ 



1089 





I APPLE EXPANSION KIT 
16K Memory Add-On a A7m 
MEMORY ADO -ON KIT " "#*'*' 



INCLUDES INSTRUCTIONS. 



130 



EDUCATION & INSTRUCTION 

UNIVERSITY degrees by mall! Bachelors, Mas- 
ters, Ph.D's . . . Free revealing details. COUN- 
SELING, Box 317-RE10, Tustln, CA 92680 

HOME study degree program In electronics engi- 
neering. 75 specialized courses also available. 
For information write: CIEE, P.O. Box 9 196, Pitts- 
burgh, PA 15224 

MAKE hydrogen fuel: Build generators with mate- 
rial from Hardware stores. Illustrated manual; 
$10.95 ppd. NEGEYE ENGINEERING, Penns- 
boro.WV 26415 

TECHNICIANS, hobbyists. "Wire wrap like the 
professionals." Send $4.00 for informative arti- 
cle. ALDOR ELECTRONIC SERVICES, 2961 In- 
dustrial Road, Suite #212R, Las Vegas, Nevada 
89109 




PLANS & KITS 



DECODE Morse and RTTY signals off the air with 
new Morse-a-Word or RTTY reader. Morse key- 
board also available. Kits or factory wired. Send 
for details, MICfiOCRAFT, Box513R, Thiensville, 
Wl 53092 (414) 241-8144. 

PARABOLIC screen mesh dish kits for weather 
and television satellite reception. Pre-cut, ready 
to assemble. Sizes up to 16 foot available. Busi- 
ness size S.A.S.E. for details to: MARBLE ELEC- 
TRONICS, 32 Sea Street. North Weymouth, MA 
02191 



TELEPHONE calls recorded automatically, unat- 
tended, build yourself for Eess than S10.00. Detail 
plans $2.50. GARRETT ELECTRONICS, 6451 Im- 
perial Avenue, San Diego. CA 92114 

7-FT giant screen TV . . . Enjoy theater-size TV 
programs at home! For latest improved instruc- 
tions and complete kit, send $15.00 . . . SHIU 
NG, Box 3276-R, Seattle, WA 98114 

ELECTRONIC toys and games. Build your own 
and save. Plans for 10 toys $5.00. MICRON, 210 
E. Belcrest Road, Belair, MD 21014 

CONVERT TV to project T picture results equal 
expensive projectors! Easily built for under 
$20.00. Instructions & lens $10.00. GENIAL 
PRODUCTS, Box 273, Woodbridge, NJ 07095 

CATALOG of electronic designs. Accessories 
for CB, ham radio, stereo and PA systems, tele- 
phone, and more. Catalog sent free upon re- 
quest. PETER-SCHMITT ENTERPRISES, Dept. 
RE, POB 07071. Milwaukee. Wl 53207 



1. 5 Volt, 3 amp, Regulated Power Supply. 
Great for TTL Projects $19.50 

2. EMM 4200A, 4K Stalk RAMs, Ceramic 
A local memory boards manufacturer 
closed. We bought the new memory 
boards and took these 420OA static RAMs 
out. They are tested and 90-day guaran- 
teed 100% good. 

Prime tested 42O0A 4K RAMs $5.50 ea. 

3. Super Saver, Micro PD4 1 1 , Ceramic 4K x 
1 dynamic RAMs 6 for $10,00. 

WE BUY SURPLUS ELECTRONIC 
INDUSTRIAL INVENTORIES 

DELTROIMIKS 

sisi bufoho highway ^»» 

ATLANTA. CA 30340 
4Q4-iSa-4Mfl 



CABLE TV descramblers and converters. Build or 
buy. For Information send $2.00. CSD COMPA- 
NY, POB 26. Hudsonvllle, Ml 49426 



one O CAPACITANCE METER .1pFto999KuF 
In o FREQUENCY COUNTER 35MHz 
klt o SQUARE WAVE GEN. 1Hz to 99KHZ- 
O OHMMETER - 3.56MHz Xtal - Reg ulated PS- Five 
8" Readouts-Low cost TTL Circuits- Automatic 
Decimal Placement-Be AMAZED -Build it for 
$50 or less, j Purchase the plans, etched P.C. 
board 4-3/4" by 6-3/4"and front pan el deca l 
for $15,291 BAGNALL ELECTRONICS, R.l u „d\ 
179 May Street. Fairfield, Conn. 06430 '"* *'*> 



KITS & COMPONENTS 

INTEGRATED circuits TTL, CMOS, linear, many 
hard to find "S" and "LS" types, resistors, 
capacitors, IC sockets, diodes and more. WEST- 
LAND ELECTRONICS, 34245 Ford Rd., West- 
land, Ml 48185. (313) 728-0650 



WANTED 



PRE-WWII and early television sets wanted. Will 
pay top dollar for any set featured in June Radio- 
Electronics issue ARNOLD CHASE, 9 Rushleigh 
Road. West Hartford. CT 061 17 

WANTED SB-104 with serial number 00450. 
01505, or 02514. Reply to: EVELYN WARNE- 
BOLDT, POB 274, St. Joe, Ml 49085. State price 
& condition. 

WANTED: Lafayette hi fi kits of the 50's, particu- 
larly KT 200 tuner, K HARRISON, P.O. BOX 24, 
Terrace Park, OH 45174 

COLLECTOR wants early Halllcrafters SX28 
SX25 S20R SX18 HT9 others! National, Hammar- 
lund. All letters answered! ROMNEY, Box 5247, 
Spartanburg, SC 29304. Keep this ad! It doesn't 
repeat. 




CIRCLE 45 ON FREE INFORMATION CARD 



O 
O 

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O 

CD 

m 
5J 

to 

CO 

o 
131 



r 




THIS! 



And put up to $10.00 in your pocket. 



LU 

6 
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132 








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AH ^p Licenced by Sinclair Research Ltd. ._ 

Microcomputer 

for everyone at 
a Micro Price 



The IHkrofkeJ 



The unique 

and valuable 

components of the MicroAce 

The MicroAce is not just another personal 
computer. Quite apart from its exceptionally low 
price, the MicroAce has two uniquely advanced 
components: the powerful BASIC interpreter, and 
the simple teach yourself BASIC manual. 

The unique versatile BASIC interpreter offers 
remarkable programming advantages: 

• Unique 'one-touch' key word entry: the 
MicroAce eliminate* a great deal of 
tiresome typing. Key word* (RUN, PRINT, 
LIST, etc.) have their own single-key entry. 

• Unique syntax check. Only lines with correct 
syntax are accepted into programs. A cursor 
identifies errors immediately. This prevents 
entry of long and complicated programs with 
faults only discovered when you try to run 
them. 

• Excellent string -hand ling capability — takes up 
to 26 string variables of any length. All strings 
can undergo all relational tests (e.g. 
comparison!. The MicroAce also has string 
input — to request a line of text when 
necessary. Strings do not need to be 
dimensioned. 

•> Up to 26 single dimension arrays. 

• FOR /NEXT loops nested up 26. 

• Variable names of any length. 

• BASIC language also handles full Boolean 
arithmetic, conditional expressions, etc. 

• Exceptionally powerful edit facilities, allows 
modification of existing program lines, 

• Randomise function, useful for games and 
secret codes, as well as more serious 
applications 

• Timer under program control. 




PEEK and POKE enable entry of machine code 
instructions, USR causes jump to a user's 
machine language sub-routine. 

• High-resolution graphics with 22 standard 
graphic symbols. 

• All characters printable in reverse under 
program control. 

• Lines of unlimited length. 

'Excellent value' indeed! 

For just M49.00 (excluding handling charge) you 
get everything you need to build a personal 
computer at home... PCB, with IC sockets for all 
ICs; case; leads for direct connection to a cassette 
recorder and television (black and white or color); 
everything! 

Yet the MicroAce really is a complete, powerful, 
full-facility computer, matching or surpassing other 
personal computers at several times the price. 

The MicroAce is programmed in BASIC, and you 
can use it to do quite literally anything, from playing 
chess to managing a business. 

The MicroAce is pleasantly straightforward to 
assemble, using a fine-tipped soldering iron. It 
immediately proves what a good job you've done: 
connect it to your TV ... link it to the mains adaptor 
... and you're ready to go. 

Fewer chips, compact design, 
volume production-more power 
per Dollar! 

The MicroAce owes its remarkable low price to its 
remarkable design: the whole system is packed on 
to fewer, newer, more powerful and advanced LSI 
chips. A single SUPER ROM, for instance, contains 
the BASIC interpreter, the character set, operating 
system, and monitor. And the MicroAce IK byte 



- a new generation of 
miniature computers 

A COMPLETE COMPUTER 
for $149.00 for 1K Kit 

Post and Packing FREE 

(Add 6% Tax for Shipments inside California) 

RAM (expandable to 2K on board) is roughly 
equivalent to 4K bytes in a conventional computer 
— typically storing 100 lines of BASIC, (Key words 
occupy only a single byte.) 

The display shows 32 characters by 24 lines. 

And Benchmark tests show that the MicroAce is 
faster than ail other personal computers. 

No other personal computer offers this unique 
combination of high capability and low price. 

The MicroAce teach-yourself 
BASIC manual. 

if the features of the BASIC interpreter mean 
little to you -don't worry. They're all explained in the 
specially-written book free with every kit! The book 
makes learning easy, exciting and enjoyable, and 
represents a complete course in BASIC 
programming-from first principles to complex 
programs. (Available separately- purchase price 
refunded if you buy a MicroAce later.) 
A hardware manual is also included with every kit. 

The MicroAce Kit: 

$149.00 with IK COMPLETE 

$169.00 with 2K 

Demand for the MicroAce is very high: use the 
coupon to order today for the earliest possible 
delivery. All orders will be despatched in strict 
rotation. If you are unsuccessful in constructing 
your kit, we will repair it for a fee of $20.00, post and 
packing FREE. Of course, you may return your 
MicroAce as received within 14 days for a full 
refund. We want you to be satisfied beyond all 
doubt — and we have no doubt that you will be. 



ZSO A microprocessor Sockets for 
chip, widely recognised TV, cassette 
as the best ewer made. recorder. 
i power 

1 Expansion '""f*- 

1 Connector UHFTV 1 SUPER 

1 i modulator \ ROM. 


1 \ Clock. \ 


HAM 1 
chips \ 


I Rugfled, 
| flush. 
Keyboard 



fv .▼-■»■ - ^ w » - 



:: 



■■■■■ 



Your MicroAce kit 
contains... 

• Printed circuit board, with 
IC sockets for all ICs. 

• Complete components set, 
including all ICs-all 
manufactured by selected 
world- leading suppliers. 

• New rugged keyboard, 
touch-sensitive, wipe-clean. 

• Ready-moulded case. 

• Leads and plugs for 
connection to domestic TV 
and cassette recorder. 
(Programs can be SAVEd 
and LOADed on to a 
portable cassette recorder.) 

• Mains adaptor of 600 mA 
at 9VDC nominal 
unregulated. 

• FREE course in BASIC 
programming and user 
manual. 



JOIN THE REVOLUTION - DON T GET LEFT 
BEHIND - ORDER YOUR MICROAGE NOW!! 



I Send Check, Money Order or quote your Credit Card No. to: 
B MicroAce 1348 East Edinger, Santa Ana, California, Zip Code 92705. 
o* phone (714) 547 2526 quoting your Credit Card Number. 



Quantity 



Description 



Unit Price 



TOTAL 





MicroAce Kit IK 


5149.00 






MicroAce Kit 2K 


$169.00 






Manual 


$10.00 






IK Upgrade Kit 


$29.00 




Shipman 
add 6% 


ts inside California 
TAX 


TOTAL 





Amex. 
Diners 
Check 

Money Order 
Master Charge 
Visa 
Card No 



Exp, Date- 



Address- 



iii 



^City 



. Stats. 



.2p. 



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CO 

m 

3> 

So 

CO 

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133 



FREE PREMIUMS 

free Soldering Iron with any order totalling S25 to S99 

Free Speaker Kit K350D6 with any order totalling S100 lo S249. 

Free Speaker System B300C10 with any order totalling S250 or more. 

Above premiums are listed in this ad. 



TUBES 

7B% OFF Sleeves ol 5, international Service master Brand 

Send for Complete Range Ql ZQOO Receiving, Industrial and Antique Typaj 







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SPEAKERS 



SYSTEMS ' 

B45OT10 
3-WAV 

* Electronic 
Crossover • 4" * 
air suspension 

woofer * 1 " mid- 
range herd dome 

* Mtg, Bkt * Input 
Power. 50 watts max 




B300C10 
2 -WAY MINI 

* 3" S oi. acoustic 
suspension woofer 

■ 2" cone type tweeter 

• Input Power; 30 
watts max. * Mtg. Bkt. 




*44, 95 pr. 



B4OOC10 

2-WAY 

• Variable brilflance 

control • Mtg. Ski, 

» 4" woofer 2" tweeter 







• i •■Hit oui'i " :■:- jE - 
t A'l maxima braouh 



pr- 




KITS' 



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MXIOTSC 

K500TtD 

KSEST20 



6"«9" 20 «. 
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5" IQ oz. 
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$32.00 $13 K 

32 M 13 9S 



2S.95 
39 95 
29.95 



12 SO 
1350 

13.50 



COAXIAL 

K400C10 ■(" 10 Ol $18 95 $3 70 

K525C20 SM" 20 oe. 20.9B 195 

K6X9C20 B'-kS 1 ' 20 Oi 27.75 11.05 

KJX10C20 rxtr 20 oe. 27.75 11.95 

□UAL CONE 

iW 8 01. ! 8 05 S ».50 



K35C06 

Kiraoio -■ 10 oe. 

KS25D10 5H- 10 OE 

KBX9D10 S-«S U 10 OE 

K<X10D10 <"»10- 10 OE, 



1395 5.95 

11.95 6.20 

17.00 6,95 

16.50 695 



* Includes. 2 spcakois. grilles, fiardwjro. wiring. 
trotPuclionv 

SEND FOR COMPUTE B»ME£ Of 
paQFEEaQNAL/QEM S MIKHTURE T7PES 



COMPONENT KITS 



Experimenter/ 
Technician 

*7.*s ea. 

In ptastto ttOM 

TD-1S 25 in kit 




Send tor complete range 




Mini Axial Lead Alum. 
Eleclrolyuc Capscilors 
1 10 470 MFD 1 6 to 50 VDC 



Service/ 

MHO 



*24. 9S ea. 

in 9-d rawer cabinet 
TO-1M 75 in kit 



PO-S 25 in kit 



Mini Radial Lead Alum. PD-M 
Electrolytic Capacitor l to 

1DO0 MFD 16 to 35 VDC 



P.M2S-S 300 m kit 



Carbon Fixed Rasistors HM2S-M 1000 in kit 

Vi watt • 5*> * 10* 

10 Ohms to 10 MEGOHMS 



HM50-S JOO in kit 



Carbon Fixed Resistors RM50-M 1000 in kit 
'/i wall ± 5* ± 10* 

10 Ohma to 10 MEGOHMS 



RESISTOR SPECIAL 
500 |J . wait 5 & 10% HosLatora 
in Pol, t,^ ?395 



30-wett Solderlnfl Iron 
Ligntweignt • Ideal tor 
PC. work and kits • 250" lip 
A-PS30 



*Z 7 



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o 

z 
O 

& 

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134 



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P.O. Box 698. Melville, N.Y. 11747 



To order call collect 

(516) 752-0060 

• VISA • MASTER CHARGE 

• CHECK • MONEY ORDER 
N.Y. STATE RESIDENTS 

ADD APPROPRIATE SALES TAX 



Add lor Shipping A Insurance 

lo 5250.00 5 3.50 

S25I.O0 lo S5O0.O0 S.00 

S501.O0 lo 5750.00 7.50 

S751.00 lo StOOO.OO 10.00 

Over- S 1000.00 12 50 

CO D s extra 



*+**+*********************+*•+****•* I 



SURPLUS 

"SELECTRIC" SPECIAL! 



"SELECTRIC" TYPEWRITER TERMINAL 

Just imagine; an IBM Model 72S "SELECTRIC" typewriter built into 
a complete table-top RS-232 terminal! These surplus terminals were 
formerly on lease and appear to be In good condition (we test 'em to 
make sure the printer is functional!.) These fantastic BCD-Coded 
terminals feature: 



•15" CARRIAGE 
•725 -SELiCTHIC" 

• RS-232 I/O 

• 132 COLUMNS 
•Sim. to IBM 2741 
•StrJ. Typewriter Kbrj. 

• MAX: 16 GPS RATE 

• 10 Chars./ Inch 

• Removeable Type Sphere 



• 134.5 BAUD I/O 
•8B Character Set 
•6 Bit BCD CODE 

• Attractive Case 

• Upper/Lower SHIFT 



ONLY 

$ 469<L° 




While we will check out each unit, we MUST offer these unique 
bargains "AS-IS": Meaning they may need some service but are 
basically operational. Add $20.00 for packing crate, you pay 
shipping on delivery. 

ALSO INCLUDES: Type balk t/O circuit boards, power supply & some data. Sorry, no power 
cord included. 



—SPECIAL OFFER!!- 

Buy 2, take 20% Off ihe Full Price— n f or *■« js/*,QO 
You Pay Only » i*V 



"SELECTRIC"* PRINTER MAINTAIHANCE MANUAL 

JUST INN We now havo available some excellent printer main tarn a nee manual?. These? are 
ine most thorough manuals we've seen. Well worth the pricer ONLY a 25.00«a. 



CFR Associates, Inc. 



MAIL ADDRESS WAREHOUSE 

'■i'i rr. '11 ISGHAH1TI STBHT 

hEWTriH NH $M\& HmL'EDMIU MASS 0I83D 



[617)372-8536 



CIRCLE 43 ON FREE INFORMATION CARD 



4Kx16 MEMORY BOARD with 64 IC chips (2102) 
in sockets. Super deal at $50 the complete board. 

'$29 AUTO SECURITY SYSTEM alarm system $7.00 

SPACE MAN toy module PC board w/mu steal IC 
synthesizer chip. ROM has 5 programs, wierd noises 

blinking LEDs $3.00 each 

DATA STATION CONSOLE w/key board 9 inch 
monitor, power supply. Logic boards broken. $80 
Send for details on this one. 

Computer video monitor chassis 9 inch, 12 volt used $40 
Computer video monitor chassis 12 inch, new $50 

Hy Gain CB chassis, trunk mount $9.00 

Govt surplus walky 
talky, used cond. 
47-55.4 mc range. 
Ant. $5 each extra. 
With data. 

$25 ea 2 for $45 

AN/PRC-6 

SEE IN THE 

DARKNESS 

IR viewer, portable, new with 

choice of one lens... close up, 

telephoto or gen. purpose. 

Requires 6 volt DC btry. $250 

Parallel ASCII-II Keyboard 

Unused $50.00 

Red LED's large 10/$1.00 

Shipping extra on all merchandise 

Meshna Inc., P0 Box 62, E, Lynn, Mass, 01904 





CIRCLE 7 ON FREE INFORMATION CARD 



CIRCLE 25 ON FREE INFORMATION CARD 



Radio Shack -Your No. 1 Parts Place® 

Low Prices and New Items Everv Dav! 



4000-Series CMO S ICs 



Low 
As 



890 



Type 


Cat. No. 


Each 


4001 


276-2401 


.99 


4011 


276-241 1 


.89 


4013 


276-2413 


1.19 


4017 


276-2417 


1.99 


4027 


276-2427 


1.19 


4511 


276-2447 


1.99 


4049 


276-2449 


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276-2460 


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4066 


276-2466 


1.59 



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276-1900 


.79 


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276-1902 


.79 


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276-1904 


.79 


74LS08 


276-1908 


.79 


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276-1915 


.89 


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276-1918 


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.99 


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276-1923 


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276-1926 


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276-1929 


1.09 


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276-1930 


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276-1931 


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276-1932 


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276-1934 


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276-1936 


1.69 


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276-1835 


1.59 



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lire As \#%* 



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Each 


7400 


276-1801 


.69 


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276-1811 


.79 


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276-1802 


.79 


7408 


276-1822 


.79 


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276-1805 


1.19 


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276-1816 


1.29 


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276-1803 


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276-1813 


.99 


7475 


276-1806 


1.09 


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276-1813 


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7490 


276-1808 


1.09 


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276-1819 


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1.49 


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276-1 831 


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276-1820 


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All 100% Prime from Ma- 
jor Manufacturers. Specs 
and Pin Out Diagram In- 
cluded with Each Device. 



Barrier Strips 
Hew! 

Low As 
I 19 

Rum ad thermoplastic. Prevent shorts. 
Ideal for audio equipment, power sup- 
plies. Terminals extend ^tsT 




Terminals 


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Each 


4 
6 
8 


274-651 
274-652 
274-653 


1.19 
1.49 
1.79 



New! 



X 



IC Tool 
Set 



195 



f ' ™ Built-in Pin 
Stralghtener 

Handy insertion and extraction 
tools handle all 14 to 16-pin de- 
vices. Both tools easily grounded. 
276-1574 Set 6.95 



Speaker Terminals 



New! 


3" 

iBHfi 




-199 


[i 


^ 




a 


« 



Just right for hi-fi, instrument or PA 
speakers. Push-terminals accept 
up to 16-ga. wire. Also has 2- 
conductor %" phone jack with seal- 
ing plug. 274-624 1.99 



Sound Effects Chip 



149 




28-Pin DIP 



SN76477. Music, explosions, phas- 
I ers, gunshots and more — almost 

any sound imaginable! Line-level 
output. 6-15VDC, With data. 
276-1765 4.49 



16K Dynamic RAM 



New! 



-1095 

lOEach 



AlRR* 



16.384x1 bits in a 16-pin DIP. Ac- 
cess time: 250 nanoseconds. Re- 
fresh: 1 millisecond. Requires +5, 
+ 12, and - 5VDC. TTL compati- 
ble. 276-2605 13.95 



Opto Devices 
I 



!-.f 



Low As 

89* 



® Emitter/Detector Pair. LED 
infrared source. Sensitive photo- 
transistor detector. 

276-142 1.99 

(D Phototransistor. Sensitive, fast 
response silicon. 276-130 .... 89c 




Cases and Cabinet 
Save "o p 33% 



CJ 




Si Deluxe "Wood Look" Cabinet, Metal, slide-oft cover, rubber feel. 

2^x4V«SVgr 270-282 (Reo. 5.95) Sale 3.95 

(3 Readout. Holds four 0.6" or einht 0.3" readouts. Removable bracket 

1*Vie*S»i4ft: 270-285 (Reg. 395) Sale 2.95 

M Clock. R>r MA- 1003 car clock. Blue lens. Accepts 3 switches (not 
hid.). Bracket, 3Ma2VfcK2r 270-303 (Reg. 5.95) Sale 3.95 




High Efficiency 



Back in Stock! 0.45V at 

1 Amp in full sunlight. 
276-123 9.99 



Mini Lamps 
New! 



Only 

tEnlarnsd QQ6 

I to show ^^#~ 
I detail 

Pkg, of 6 



Long lite red incan- 
descents for models, 
charts, dial fights, 
more. 6V, 60 mA. 
272-1144 .... 6/99* 



Yellow 0.3" 
LED Readout 

New! 

1 99 



<s>- 




T 



Pkg. of 2 



Right hand decimal, 3.0V/ 
segment (a 20 mA. Com- 
mon cathode. 
276-067 Palr/1.99 



TV RF Modulator Board 



Save 

29% 



Reg. 16.95 

1195 




Etched, drilled & labeled PC boaid with pre- 
wired RF module and back-of-sel ant. 
switch, Ch. 3 or 4 out. Produces color or 
b&w video, 30-15,000 Hi hi-li sound. With 
instructions. Pans extra. 
277-122 Sale 11.95 



16-Pin DIP Jumper 
Cable 



NW. 



^3 



99 



Two 16-pin DIP plugs connected by an 
18' color-indexed ribbon cable. Simpli- 
fies linking up digital circuits. 
276-1976 3.99 




AC Cooling Fan 

Quiet, Efficient 



14 



95 



Regulated 12VDC Supply 

2995 



Ideal for cooling hi-fi and ham 
equipment, power supplies, com- 
puters. 70 CFM. For 120 VAC. Just 
4.63x4.63x2.47" overall. 
273-241 14.95 




Circuit 
Breaker 

Protected 



Powers CBs. ham rigs, auto-sound equip- 
ment and more from 120VAC. 2.5A continu- 
ous. 5A surge. 2Mx4Vfex6#i: U.L listed. 
22-124 , 29.95 



Prices may vary at individual stores and dealers 



NEW 1981 Catalog Available Now! Come in 
for Your FREE Copy! (None Sent by Mail). 



Radio /hack 

A DIVISION OF TANDY CORPORATION « FORT WORTrf TEXAS 76102 
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O 

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3 

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135 



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SSM740IN 
SN7402N 
SNH03N 
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7400 TTL 

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SNHWN ,4 

5NMWN .» 

5r4747tN 5.00 

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5ft7*BH 49 

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snhj.cn .a 

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5M74S3Q0 4 « 

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SN74279N .74 

5NJ4i*JN 2.25 

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CD4OC0 


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CD40QE 


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CO406J 


.39 


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CO40IQ .«. 

CD4071 .49 

cdiot: ,«■> 

CD4QK 1,« 

CD40tl .77 

CD4QC2 ,.?) 

CD4W3 .» 

CD4&M 1,19 

UC144M |4.)G 

UC14410 14.B 

MCJJ441I I4.H 

MC1W19 4,» 

WC144JJ S3.*5 

MC14M5 .« 
MC14&Q7 

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cocstd 

CD«1I 
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CDtDlt 
CD4520 



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74C41 
74C4( 
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74C74 



74C00 



74CB 
74C90 
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74C» 
MC1I37 
74CI51 

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74C1C0 

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7,B 
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74C16J 
74C16* 
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LWSO&ht .79 

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LWMSH UO 
LM-KHK 
L.M31CCN 
LMJ11N/H 
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(-MJllCN^H 1.95 

Lr.:;i5ri Ud 

LM3MK-5 ].3V 

LM12QK-5.; JJS 

LMETJK-lj L3 

LMEflK-li 1.% 

LM13JK-K ].» 

LM3aOT4 L2S 

LMOTT-SJ 1.2 

LM33or-t i.a 

LMJMT-12 1.2 

LMiMT-J5 L3 

LM1MT-H La 

LMJQ0T-24 L2 

LM33JK-5 5,B 

LM324N M 

LMJHN ,99 

LM34flK^5 J,B 

LM340K-& LB 

LM340K-1 1,35 

LM340K12 l.li 

LM340K IS LB 



LINEAR 



La 

1.3 



LMWK-JJ 1JS 

LMHQK-34 L» 

LMW(rr-5 

LM34QT4 

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LM3*0T-J2 1,3 

LM3*lT'ia i.a 

LM3»T^U 1.S 

LMJ441T-J4 l.S 

LMfilN 1J0O 

LMiTIfN LB 

LMJMN 3.K 

LM377M 2B 

LMJMN LB 

LMMOCN .99 

LMJBH 1.79 

LM3CN 1.79 

MtSlflA 6,00 

NES29A 4.1S 

rVE5J]i4/V 3kB 

NesST 6.W 

NEMO 5.M 

NC54.1N 4,B 

NEHON ]..» 

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NEi54N ,99 

NtSSOH *,« 

NE56?B 5.03 

LM&65N/H L2 

LMU6CN LB 

LKKH7V/H .50 

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LM70JCN/H .69 

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LM710N ,71 

LM711IX Jf 

LM723N/H AS 

LW733N J.>- 

LM739N 1,1 i 

LM741CH/H J& 
LMT41-14N J9 
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LMI4S6CN/H .W 
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MCJ4WN LB 
LM14WN ,B 

LMtS&fiV 3.75 
MCiT41SC^ 3.aj 
LMH1JN LB 
LM29Q1N LB 
LM30UN ].W 
LM3CUN 1,49 
LW3^MN(J40S),69 
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7»^1CN 

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RC41X 

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4,95 



3.K 
4.B 
4.44 



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?il_S0J 
74LS04 
74LS06 
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74LSW 
74LS10 
74 LSI 1 
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74LSI5 
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74LS40 
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74LS0OTTL 

MLSS3 ,29 

74LS4 _M 

74LSB .a 

74LS7J .54 

74L5H .54 

74LSB ,71 

74LS4 ,44 

74LS7I L 49 

74LS13 LH 

74LSI5 L» 

74L5» M 

74LSM ,J1 

74UH2 ,« 

J4LS93 ,90 

74LSB M 

HL3B Ll| 

74LS107 ,W 

74L51D9 .54 

74LS112 44 

74LS1J3 L» 

74LS13 J.M 

74L-51J? ,99 

74LS1J6 ,59 

HLS1M LB 



7JLSIM 
74L5151 

HLsm 

74L5147 
74LS1H 
7JLS16t 
74LSM2 
74US1S3 
74LSLM 
74LS1T5 
74LS1B1 
74LSL90 
74L51H 
74LSl$a 
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HL.S1SM 
74LS195 
7JL5»1 
74LS»7 
74LS3I 
74LS2U 
74LSJ79 
74LS3S7 
74LS3U 
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JE6Q8 PROGRAMMER 

Z704/27QB EPROM PROGRAMMER 

h. Mj„ir.^,n, w i ud irn Ort M—r, m.. rk.p^uwwM^ 




H^r li HIM ■ » ■■ <m t 



H'(1.'..^l..l 



*— M i l I I I II t l|>^ll UI kwt — — . m» 

U. m< * Kt^lm tut- »p4 MHiMlhh 
hpvimiwiii I1IVAC «-.■ I*i 



»* Li i.'Hii|i*iin-n 



■r»i n tc i <H< xt<u4^f 



•' w^.ijvw-av TKH.Uk««£ n t H ,iXaDt«l»i l P M il« l 



JE603K KIT $399.95 

JE606A Assembled and tested $499.95 



DISCRETE LEDS 



XCS56R Jffl" n* 

XCH6G .200" sr«n 

XC5WC .200" 1 cl«ir 

XC22R .200" f»a 

xc?;o -200" gf*flH 

XC2Y .S»" 1 y*lls^ 4A1 

MVEOB .170" red 



5/11 


MVS0 


.i-i 1 


rid 


W* 


4#1 


KC»JR 


.171' 


rid 


Ihrtl 


4/tl 


XC209Q 
XC2WV 


l^i 1 


gratn 


<rtl 


4^1 


.13' 


yellow 


*/« 


5/11 


xc5?jr 


:•.:■ 


r*4 


Vtl 


i/H 


xaxc 


if-, 1 


gr**n 


i n 


4rti 


XC9SY 


IB? 


yallQW 


4.V, 


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XC5KC 


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cl*«r 


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XCU1R .140" red i/ll 

XCUlQ .IW'grBfln 4^1 

XCUlV ,HV"y*H4w 4^S1 

:-:c:JlC .ItO" slmar *;',; 

INFRA-RED LED 

V'KV'KIVII" llkl 
IRL-Syjl 



C,A. — Com man Anode 



Typ* 

HANJ 
MAN 7 
MAN 1 
MAN 4 
MAN ':.; 
MAN 7Y 
MAN R 
MAN T4 
MANS 
MfiNH 
MAIM 3620 
MAN »» 
MAN 3$40 
MAN 4610 
MAN 4110 
MAN 440 
MAN 6610 
MAN 66X 
MANEU) 
MAN KM 
MAN 6664 
MAN 6710 
MAN 6750 
MAN «7& 
MAN t7» 
DLHI 



Polirkty 
e.A.-rid 

5x7 D. *.■ i . I 
C.C.— rid 
C.C.-r»d 
CrA-— gcflen 
G. A--~ynl l o* 
CA-— rod 
C.C.— red 

c.A."veirt>tar 

C-C— ytMsw 
G,A, — orange 
ClA. — orange i 1 
C.C T "or*n9e 

e.A,— orertge 
Cflu— yellow 
CC— yellow 
C. A. — Orange— D D 
CrA.— Cf«ngc. t I 
C,C."Ofin«-DD 
C.C.— orang* : | 
C.Pu— orange 
C.A.— refl— DO 
C.C— iBCJ t 1 
C.A/-ridi 
C.C-"f*£l 
C,A— fed I 1 
C.C.- red 



DISPLAY LE0S 



C.C. 



Comrr 



Ht Price 

.;ro ?.« 

■ -V.0 4.B 
.125 



us 



Type 

OL7D7 

DL72 

D4-741 

z- >..:■■: 

DLMJ 

DL7S0 

OL31B 

FN DTD 

i NQ-y 

FND3S9 

FNDS0J 

FND«7 

50ftZ-7T» 

HDSP-34M 

HDSP^i*03 

»C-H13 

5M2-7620 

50tt-74iZl 

S0G-77X 

50t2-mi 

5OJ2-7750 

aBJ-7751 

M42-77S0 

b«G-7j0a 

S0t2'7302 

50*2-7304 

1052-7340 



Poliritv I 

C t An— red 

C.C— red 

C r A,-rod 

C.A,— fed i 1 

CtA,— red 

C.C— red 

C.C .-red 

C-C 

C>C s I 

CC|FND500| 

C.A. (FND510) 

C.A. r fl o 

C.A,— red 

C.C— red 

C.C-, R,H.O.— red , 

e.A,, LKO.-yii. . 

C-C, R,H.O,— yd, , 
C.A,, L.H.CI,— red . 
CA. b R.H.Q.— red . 
C.A., L.H.O.— red . 
C.A,, R.M.G.-red . 
C-C„ H.HO,-rtd , 
4x7131. dis. RUDP . 
4x7ql.difl, LHDP . 
Qverng*. che r. ■£ 1 1) . 
4*7lgl. dig. ne«. 



1.50 
1-ffi 
L& 
1.3 
,99 
L2S 
1J5 
LS 
1.5 
19.B 
ll.fi 
15,00 
22.50 



RCA LINEAR 



CA30J3T 2.11 

CA20J3T 3 r 3 

CAJuBT ZM 

CAJ0BT 1.35 

CA3046N 1.30 

CA3D59N 13 

CA306ON ].3 

CA304OT L3 

CAHilM 3,00 



CAXCZN ?J0Q 

CA30UN J_W 

CA30KN JH 

CA30BN i.75 

CA3JUT 1J9 

CA31MT L3 

CAJliOT 1^5 

CA340IN 49 
150 



CALCULATOR 
CHIPS'-DRIVEHS 
MM57S » r fi 
MUS73V Z.95 

DMMft ?,00 

DMJ*=5 1.00 

DM1H7 ,a 

GMtm .a 

1IH 7-te«. 
LLDctrlver 140 
MMDOt 4.B 



W^ 



LOW PROFILE 
(TIN} SOCKETS 



t pin LP 
14 rin LP 

»p!n, LP 
I£pln LP 
M pin LP 
22 pin LP 
2* pin LP 
38 Pin LP 
Bpln LP 
40 pin LP 



■j|j|r< 

t pin SG 
M pin SO 

16 pin 5G 
IS pin so 
:J !--■■» 'i'-i 

2t pin SG 
36 pin SG 

40 Pin SG 



SOLDERTAIL{GGLD) 
STANDARD 



MM5311 

MM53L2 
MM5314 
MM53I6 
WM5JLI 
MM5309 
MM5J77 



4.U 

4.» 
4.fi 
4.« 

e.» 
?.fi 

2.fi 
4.B 



MM5H7/]99B*4.« 



MOTOROLA 

MCI4HL7 4.B 

MC140lLi 5.75 

MCI439L ?.« 

MC3fl23P 2.B 

MC30UP 340 

MC4DK[744i,LH 

MC4CT24P 115 

MC4O40P 6.B 

MC4044P 4,60 



SOLDER TAIL 
STANDARD (TIN) 



14 pin ST 
It Pin ST 
It pin ST 

21 pin ST 

3pLmST 
* Pin ST 

40 pin ST 



I 

1 pin WW 

LOOIn '.VW 
14 pin WW 
J£ pin WW 
11 pin WW 
20pln WW 
22 Pin WW 
24 p|n WW 
2*ptn WW 
Bpln WW 
40 pin WW 



WERE WRAP SOCKETS 
(GOLD) LEVEL #3 



L35 
LM 
1,53 



1/4 WATT RESISTOR ASSORTMENTS -5% 



tD CHI* I? EMI 15 OMW Eg OhfU 7/ ffeiU 

;:f»^i JUrjnH MGUl 4- OHM »QHM 

BG*fU traMJ tCOSHiM 170OAI i»Qh«l 

IB 0HU 270 DHW ,'7TJ 0*dJ i» OHM 150 OHM 

J'i: Driy ¥4 HUM blO 0KM *^| MriV f JB 

Lftl !.:■» t.m 

3-3" 1> 4,71 



77k 



:5> 

HK 



in 



I7» 
I.7U 
3,3U 



m 

UK 

270k 



*M 



««3 51^95 

mpm $1.95 

N pcs $1 .95 

wpcs $1.95 

upci Si. 95 

hpci $1-95 

»Pti $1-95 
ASST. 8R includes Resistor Assortments 1-7(350 PCS.) $10.95 ea. 



I.UI 

4TW 



1f> 



IN 



S10.00 Min. Ord*r - U.S. Funds Only Spec Sheet* - 2Sri 

Cillf. Rtiid4nIiAddfi%S>leiTax 1931 Cualofl Available -Sand 4^*timp 

Pasfaoa) - Add SK plu 1 5 1 1 nsurance {if deiir ad ) 

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TELEPHONE/KEYBOAflD CHIPS 

AV44100 PU111 Button T«l.ph(inf OialHf 

AYWffll Repertory Ot*l«or 

AV44SD0 CMOS Clock acnantor 

AY"l.?jre KsVOQird Encoder l« kfiytj 

HL.cu^ Kflyuoifd Encoder 16 k*yi 

."cn^! Kevboi.d Encoder [16 k«yt) 

T^cgzi Key6o*,0 Encodtr [20 k.yi) 



n.ss 



ICM CHIPS 

IWTfXS CMOS tasg< riwir 

C V ■ : : S CMOS If D SUWliauTirair 

UMTUn 0W»t« Coffloikf 

ICW^tM Sfiw D«aoi C*jnt«r 

ICMWK) CtootG 



2i Si 
IS 9S 

7» 

IS Si 
G.9S 



NMOS READ ONLY MEMORIES 

UCMGV1 I3S X 9 K 7 ASCII Milt« <atln Crflt 13 SO 

«CH 6S H IM I 9 It r Mi* Symbol 1 Piau* 13 SO 

MCW6SJ5 IMXSirUghiEoMigiaiiru'ln 13 SO 



MISCELLANEOUS 

TLOHCN Hud Low Nsnt tji-M Op *mt> J. 19 

TLJ9JC1 SMldJiIng KMuUlor 4.4t 

tUatEP Sinjil Swldiing Rtgulimr 1.75 

11C90 Omot 10/11 Pnsolr H.s 

5SH90 Hi-SlMd "Mil 10/11 pmolii 11 95 

W! rYcU'Dirluigliin 0fU->HilUr LS 

MKMtMO Top Ocuyt fna, rsw«ni w |7 K 

DSOOJSCH SMKi !jJusi M0S tkB drfint 3.75 

TIL300 2T ftfl num. display w/inug lojv- tjiio 10. OS 

■■"■' :■ TV Casmra Syne GpHfitor H.» 

MMi330 <W Digit DPH Loo.l Olaci IStMClal] 3.1S 

LD110/1II 3Vi Oljil MD CgnwlB M 2S.00IH1 

MC1U1JP 31y Digit AjD Convinir 13 54 



LITR0NIX ISO-LIT 1 

Pluto Tranustor Qplo-liolllof 
(Slim as HCT 3 w 4WJS) 

49ti each 



SNTH7J 

SOUND GENEPJTOfl 
GtniyjtK Cornpt*, Sournts 
Lou* Fmr - Proarwnfnabti 

S3.95 each 



TV DAME CHIP AND CRYSTAL 

AY-3-SS00-1 ud 2.01 MHZCtys&l ICItlp t Cnjstll t nc , 

incl-Jdtl jgaic ilisjiiy 6 qjnin nd nkct J-i-liji [I: 7 .9p/SGt 



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XRE10 
IH315 

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Xn-LSiS 1.54 

XRS55 .39 

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JtBMTCP .99 

XR55JCT 1 !S 

XH1310P 1.9S 

XR1468CN 1«5 

XRUM 1 9S 

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XR2211 5-25 

tfn2212 4.SS 

XA3240 3.45 



XR2Z42CP 1 50 
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XR4136 
KH4151 
XFH1W 
XIM202 
XR4212 
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XH4741 



370 
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1.25 
1.25 
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145 
3.50 
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1.15 
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TtF! V0LT1 W 

IHr-4* 33 400n 

TN751 S J 400rn 

ruraa s.« *»n 

1N7I3 5 2 4CKn 

XHTSf $<3 400m 

IH7H 42 a J :<n- 

IK»9 8 2 +M01 

1N865 15 400ni 

11.1232 5. t> 50C«I 

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1.KH3S C 1 Ufa 

IKtift 7 5 500»i 

UiO*2 li jQOffl 

1NK45 IS 500,11 

JN45* 2S 40m 

tMSt -:o >■ 

tN45S4 1*3 10m 
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4-100 
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4.1 DO 



4.'1DTJ 
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1N44J02 lOOmiMUP 

IWIKrt HJ0PW1 WP 

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1 H40C6 BOO FIV I rUtP 

I H*m 1000 PIV 1 MIF 

1M3H0 SO 20hn 

FMI4I 75 'On 

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CAPACITOR SSSSSS CORNER 



icrr 
22 pi 
47 ft! 

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220 pi 
470 M 



0022 

0047ml 
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4f/3W 
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47/50V 
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12 ID 07 023T4 
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1! 10 07 22*TH .33 7J 71 
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■» J* -29 l5,2aV LM 1^ ,95 

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,79 ,Sfl .SI JWliV .25 Jl .U 

H .71 ■» 470/2SV .3S Jl JTJ 



136 



CIRCLE 29 OH FREE INFORMATION CARD 



BLAK-RAY Ultraviolet 
Intensity Meter 




TWO MODELS: 
LONG WAVE 

AND 
SHORT WAVE 



Meter consists of 3 sensor cell attached to 
a compact (3" x 3J1" x 3") metering unit. 
Can be hand-held or placed directly on 
surface for measuring. Can be used re- 
motely, while connected to a meter hous- 
ing by a 4-foot extension cord. Two 
models available - one for long wave 
and one for short wave ultraviolet. Read- 
ings are in microwatts per square centi- 
meter. Weight: 1 lb. 

Completely assembled [includes sensor 
celt, reduction screen, extension cord, 
contrast filter and certification report.) 

J -221 LONGWAVE ^ n .- __ 
(3Q0nm-4O0nm) $242.00 

J -225 SHORT WAVE ft 
(200.nm-280.nm) IpZOU.UU 



EPROM Erasing Lamp 




* Emms 2708. 2716, 17U2A, 5203a 52040, ote. 

* Erase i up to 4 chips within 20 minutes 

* Maintains constant exposure distance of one inch 

* Special conductive foam liner eliminates static 
build-up 

* Built-in safety lock to prevent UV exposure 

* Compact - only 7-5/8" X 2-7/8" x 2" 

* Complete with holding tray for 4 chips 

UVS-11E $79.50 



Jumbo 6-Digit Clock Kit 




■ foor JjaVlvt. and two JWht. 

cam mo n ;■..;■; displays 

* Uui MMSjii dock chip 

* Switch*)* lor hours* mint! l« in d Hold runt 1 1 on* 

* Haurt gully vlCWltll* to W feet 

* Simulated walnut cue 

* tlSVAC operation 

* 12 or 24 hour upui jlio ■■■ 

* lntiudci.an component*, caw a no wall Uansformc,- 
i Sua: 6>. x 1W x i* 

JE747 $29.95 




JE701 



■♦E3r-.cn-. .300 hi, CO mm. cith- 

□rJi display 
rgsit MM&314 clock chip 
*3»*v nchei far houn, nnnu[« 

■nd hold mndas 
• Hri. eiiiiv viawaDia 10 20 It. 

► Simulated w*inin. UH 
•115 VAC OPcr.i1 en 
•12 Or 24 hr. cpafaElon 

■ IneL ill temponinu, cue & 
wall tren ilOrmar 

■ Sua: 5V x 3 1 'E" X 1 fc" 



6-Digit Clock Kit $19,95 



Regulated Power Supply 



Uses LM3Q9K. Heat sink 
provided. PC board con- — 
Etructtan. Provides b jolfd ~~ 

1 amp ft? 5 vol is. Can supply up 
to '5V, r9V and ^12V with 
JE205 Adapter. Includes compo- 
nents, hardware and instruction*. 
Si»;3.Vx 5" x2"H 



JE200 



514.95 





ADAPTER BOARD 
-Adapts to JE200- 
+5V, +9V and ±12V 



DC'DC converter with +5V input. Toriodsl hi- 
speed switching XMFR. Short circuit protection. 
PC board construction, Piggyback t° JE 200 
board, Siie: 3W" i2"k 9/1 6" H 

^£205 $12.95 



MICROPROCESSOR COMPONENTS 



-tMIMtH* BttHHtT DCVtCa- 



12 1 7 
614 
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OH 
Kl* 

b:jj 

P51 
IS3 
KSI 

137 

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HORN 



Rag toftm* T^IUSAHR 
hag. Mmrfl Tiirw 
pub r*** id iPfti 
pits rjiucewol 
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m*a 

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UPU w* Ogcl irf Ran. 

IKI 5t*it Rpi* 

Pi*** inw Uaai nUQMLtti 

fteoifly Irtff !,!-< Cvwcpfltr 

>r>iiu Be POM IUOM30-1I 

ASjUtfifanStiCir-rn •uiic'jr 

SjTetfeLanoui Sana DiU AoHE 
tHOO m Dw UOCEU 
Hffl w: UoouMfdt 
auadaSWilka Ifi« <WC4I3<E|. 



B13(Z,4rDj CWtOW9aanBt1b>ppfi ««, 

nil wi " 

an 

uusnn pwi tw nan o-* Ubntarr 



S14.» 

13.H 
<1JS 

T.tl 

lQ-Si 
RB 
6,tt 
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!2-ft 
7^5 



«Wib i;. cpj 

aipiwa cru 

JtE-3 UPU 

BDi cm 

KLT5ISUS I &| MPU .,• 

PW65 CPU 

THSHOUL 16-11.' MPU 



not 
ifn 
iiEittmon 

7107 

2UCQ 

■-n.li". 

7117 

71 U 

71 Ml 

7IH-3 

JM4L-3 

5101 

M*371Pr 

74« 

Lhfnjjl4. 

tUHQW 
MMJ2B-! 

tUWOM 

4S.SIL 
TU540IJ 



TWA I SUAc 

TEQilEI Oirmtntc 

7MX4 Sue 

10«1 St!^ 

tESWXI StAc 

HOT SUM 

7WH SUicUOS 

ICC4X4 ftiM 4 Kh* 

itH«4 SlAc 4U« Lew pow 

1EWH stWc SOnx 

IftUXI 5UH 30ftU b« £«>«' 

ISSX4 Sue 

4095X1 DfWK 

ItUU fine 

4X DXTBITK Its EWI 

15K Oftut 



i0?«* JUix 
IrS.SHXl Bt/iwnx )Mni 



UK 



- : r :i!T HtDISTEHS- 



UMilijVI 
WWWltJi 
750KHW 
StJ 

:xz 

ton 

7U? 
7S7I 

7S» 
2SO 



Dju 25- &; Chjnime 
Dull SO tt uViunve 
puU tr» G.1 »|K 

□ml EJ EM MnnuliUi 
SG0SI7 frl Dpii-Tyc 
AJ1IH4 Ch-ii-n-E 
■In 33 C: !;.:.!■:; 
LUil U; EM StilK 
it J Bit DvnamLc 
•■:;:i i-- .i-i : 
Dun :** 9.1 sale 

HjjJ 7S0 Slttc 
ffuU J4U Brl 5ffK 
ttutl M frl SUln 

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: k 

2H 

4.00 
4U0 
J« 
SB 



17074 2041 HMOS 

f7lfl 1(K + EPflOHtlntalf 

" '.■■::■'. it i>- sn^M(?rLfr) 

J Hi*flutf« aiV* '5V{a»iiiii 

TMSIJ-3? 4KU EPROu 

77M K EPtiOW 

rTiit.i in" 



1595 
79-» 



-UMT'S- 



*-r-j-rQ13l M* P 



52M 7041 

BWMtflltl] 157* 
»3a-H7fi&7) ?M 
I7S27 3£C| 

ITSTIa *QH 

mmaasoxn 

74IB S13 

r4iii ;» 

74S2Sr 1024 



PROM 



-5V 



Function 
Generator Kit 









tA" 

















Provide* 3 basic 
wivaforr«j. una, 
trrtnglt tr*i KiUJire 
wive, Frtaj. Mrtga 
Iron 1 HitolCMK 
Hi. Output ampli- 
tude from ■join 
to ctvar t» voltt 
r,p*a'k to p«kl. 
Ut*t • 12V sMPPtv 
of a i6V spi.t Wfj. 
ply- InclLtdaj chip. 
P.C- &oairJ, com- 
pontrtti & in^ruc- 
lions. 



JE2206B....*19.95 



DIGITAL 
THERMOMETER KIT 




• Dull i»rnon— COriTrol Poller, for indoor/ 
DiJidaor Or dual rr.on I'O'inO - c:iH-:iiiQri 
up to GOO ItHit 

■ Com -iiuooi LtD .8" h t. dEipltv 

■ Ringo- 401^ to 19S*F / -40*C ID 100'C 
■Accuracy :l*rtominii 

■ Callbnufor Fih'9nhB\t/Cmt%\iiM rajidinQ 
■Sim. wiitiut ca«- AC wall n±aptar iincl. 

■ Sub 3K"H x 6-s;B"w x 1-3/&'"D 



JE300 



.S39.95 



DESIGNERS' SERIES 
Blank Desk-Top Electronic Enclosures 

• Hbh strength ipoxy molded 
«ivd piBMi in mocfii 




: [lieccs in nioclu brawn 
finish. 

Sliding rear/bottom panel for 

v.'rvicr and coiiiri unc-ni. tc- 

ctiiibiSity, 

Tup / Lotto m panels X80 thh 
alum. Alodine type 1200 
finish 'vdIi.I tint color) far 
best pi i rut id lie sin a ifitr 
mod if Ration, 

Vintsd top and bottom 
paneli for cooling tffkitnev. 
Rigid construction provides 
unlimited applications 

Tht "DTE" Blank Detk Top Electronic Endosurasars designed to blend and complement 
today's modern computer equipment and can be used in both industrial and home. The 
end pieces are precision molded with an internal slot [all around] to accept both top and! 
bottom panels. The panels are then fattened to W thick tabs ins-id e the end pisuito 
provide maximum rigidity to the ancinsura. For easa of equipment sen vicing, (he tear/ 
bottom panel tildes back on slotted tracks while the rest of tha enclosure remains in- 
tact. Different panel widths may be used while maintaining a common profile outline. 
The molded end piecei can alto be painted to match any panel color schema. 



CONSTRUCTION; 




Enclosure 
Modal No, 


Panel 
Width 


PHtCE 


DTE-S 


8.00" 


$29.36 


DTE-11 


10.65" 


S32.95 


DTE-14 


14.00" 


S34.95 



$1000 Mm. Order - U.S. Fundi Only Sp*c StrMtJ - 2SJ 

C*1 r.1 . R ■udartti Add 6 % Slta Tax 1 981 Catnlofl Awilabla - Sand 4 1 d sum p 

Portage- Ad rfSSpELn Si In sun no* ( if d Mir ad] 

PHONE 

ORDERS 

WELCOME 

1416) 592-8097 

MAIL ORDER ELECTRONICS - WORLDWIDE 
135S SHOBEWAY ROAD, BELMONT, CA 94002 




PRICES SUBJECT TO CHANGE 





2 rational Semiconductor 

f RAM SALE 

MM5290J-2(MK4iwupD*if)i. - - $6.96 each 

T6K DYNAMIC HAM It SONS) 

(3 EACH S4S 351 (100 EACH $550 DO/Ioi I 

MM5298J-3A $3.25 each 

SK DVNAMICHAMfLOWHAL^OF MM5290JI 200TJS 
18 EACH Silo 51 1100 EACH RSO.Wot! 

MM2114-3 S5.95euch 

*K STATIC RAM 13O0NB1 

18 EACH S43.35I (tOO EACH Mrjo.OOAnt! 

MM2114L-3 SS.25each 

•IK STATIC BAM tLOW POWER 300NS) 

IB EACH sa*.9S) HOP EACH. S47S.00floll 

Vacuum Vise 

\ f a e warn ■ bat* j Ught-Eluty 
vii* tor small comp-Din*iTii 
and att*mblirs A6S con 
irMCtlOn. 13*'" famn, 1M" 
raval.Can ho pormi nam E 1^ 
InRallad, 

VV-1 $3.49 

TRS-80 
16K Conversion Kit 

Expand your -iK THS-U0 SvKflrn to t6K, 

Kit comtt complc-ie with: 

*8 cacti MM529Q.2 (UPD41Gf 416K Dynamic Rami] 

1EONS 
* Documantaiion for conta rsion 

TRS-16K $49.95 

JE610 ASCII 
Encoded Keyboard Kit 

Tne JES10 ASCII Keyboard Kit can be interfaced <mc 
moil any campy tor iyitam. The kit comet compiate 
With an induitrial grade keyboard twitch altambly 
1162-lceyir. IC'x^ ietckats f CO"n«lOf h eteccrOnk: compo- 
nant* and 9 do utile- sided printed wiring board. The 
keyboard ■isembly require! +5V @ 150mA and -12V 
trjmA for opereilOin, Ftatuntc: GO keys generate ihe 
126 charterers, upper enrj lower cue ASCI I ivt. 
Fully buffered, Two uier-define keyi provided tar 
cuitom applications. Capi lock lor U pper-caue^only 
alphe characters. Ulill-iei a 2376 1.40-pin) encc-dej 
read-only memory chip. Outputi direciLy compatible 
With TTL/DTL or MOS lojic arrays. Eajy Interfacing 
with ■ 16'pi.n dip or 13-pln edge connector. 

JE610 (Case not included) $79-95 

DeskTop Enclosure for 
JE610 ASCII Encoded Keyboard Kit 

Compact d*5k-tcp enclosure: Color^coordinatM da- 
iigner's, caw with light tan aluminum panaEi and molded 
end picOrjs in mncha hf OWn . Includaimountinshcrdwara. 
Size; 3K"H x 14^ "W x B34"D. 

DTE-AK $49.95 

SPECIAL JE610/DTE-AK FUflCHASED TOGETHER 

jValue $129.90) $124.95 

JE600 
Hexadecimal Encoder Kit 

FULL SHIT ktm \ 

LATCHED OUTPUT ^K ^^K \ 

19 KEY KEYBOARD ^^ " aaaa^"" \ 

The JE60Q Encoder Kayboafd Kit providcttwo leparate 

haxadeclmal dlprli produced from sequential key cntnex 

to alloirv d^reci prcHgremming tor cVbit microproceuar 
or 8-bit memory circuits. Three additional keys are 
provided lor user OparAtKini with one having a buyable 
output aval labia. The outouliare latched and monitored 
with 3 LED read quel Also included iie key entry strobe, 
Featurai: Full B'b'U lalched output for m icfoprocflHor 
Uirt. Three uwrdeline keys with one being bistable 
operation, Debounec circuit provided for all 13 keys. 
9 LED rcjtdouti to Verify eninei. Ea<y interfacing with. 
standard 16 pin LC connector. Only ^5VDC reqtlired for 
operation, 

JE600 (Cut not included! $59.95 

Desk-Top Enclosure for 
JE600 Hexadecimal Keyboard Kit 

Compact datk-lop oxoloturt^ Color-coordrnBtHd dc 
■ignar's caw with tight tin aluminum pamtll and moldad 
and oiecosm maehjhiflwr. Includes mounting hardwari. 
Stai 3!4 "H m BX"W !t est"D. 

DTE-HK $44.95 

SPECIAL: JES00/DTE-HK PURCHASED TOGETHER 
(Value $104.90) S99.95 J 




CIRCLE 30 ON FREE INFORMATION CARD 



O 
O 

m 
a 

OS 

o 
137 



2. 

138 



SPECIAL 



AN 214Q 
TA 7205P 
2SQ1308K 



1.45 
1.70 
2.50 



MIN 10 PIECES PER TYPE 



EXACT REPLACEMENT TO ECG 


1 ■ 9 


i g 


1 -9 


1 -9 


100 


1 00 


1(59 


1 50 


7--:8 


3.50 


336 


25.00 


101 


1.00 


170 


3.90 


259 


2 70 


337 


15.00 


102 


1.10 


I71A 


0.1X1 


260 


4.70 


338 


16.00 


102A 


0.75 


172 A 


0.40 


261 


1.40 


339 


23 00 


103 


1.10 


173BP 600 


262 


1 40 


340 


1.90 


103A 


80 


175 


1.30 


263 


1 60 


371 


145 


104 


2,00 


176 


1.00 


264 


2.00 


374 


1 55 


105 


2.20 


m 


0.25 


265 


i oo 


376 


1.80 


106 


40 


178MP05O 


266 


0.90 


376 


2 30 


107 


60 


179 


5.00 


267 


1.00 


380 


3.60 


108 


75 


180 


4.00 


268 


1.20 


361 


3.60 


109 


0.30 


181 


290 


269 


1 30 


396 


2 10 


110MP0.50 


182 


2.50 


2/U 


3.30 


397 


2.30 


111 


1 20 


183 


3.00 


271 


4.50 


409 


I 30 


112 


0.80 


184 


1.00 


272 


80 


416 


i 10 


113A 


80 


185 


1 20 


273 


1.20 


428 


0,80 


114 


ceo 


186 


0.90 


274 


2.60 


519 


0.40 


115 


0.80 


186 A 


1.20 


275 


3 00 


524 


1.50 


US 


0.30 


187 


1.10 


2/6 


7.75 


551 


1.60 


117 


0.30 


187A 


1.30 


277 


9.80 


601 


025 


118 


130 


188 


1.50 


278 


2,50 


703A 


1.20 


119 


1.00 


169 


1.40 


279 


5.00 


708 


1.50 


120 


0.90 


190 


1.80 


280 


3.40 


709 


2.60 


121 


2.70 


191 


2.00 


281 


4.60 


710 


2 60 


122 


400 


192 


0.45 


2B2 


3.10 


71? 


1.80 


123 


0.60 


193 


0,45 


283 


6.00 


713 


1.50 


123A 


0.55 


194 


0.45 


284 


4.20 


714 


2. SO 


123AP 0.70 


195A 


1 90 


285 


5,70 


715 


3.00 


124 


1.60 


1S6 


1.20 


286 


5.50 


718 


1.50 


125 


0.30 


197 


1.30 


287 


60 


719 


150 


126 


1.20 


198 


1.40 


288 


0,70 


720 


1.50 


127 


400 


i«y 


0.40 


289 


0.60 


722 


' 50 


128 


0.85 


209 


030 


290 


0.60 


723 


l 60 


129 


1.00 


210 


O.Ub 


291 


1,30 


724 


2.60 


130 


1.30 


211 


1,00 


292 


1.50 


731 


3.80 


131 


100 


213 


10.00 


293 


080 


7^7 


3.50 


132 


0.60 


218 


2.70 


294 


1.00 


7,18 


4.10 


133 


55 


2iy 


3.50 


295 


0.60 


740A 


2.20 


1 34 A 


50 


2 20, 


1.60 


297 


0.90 


742 


3.90 


135 A 


05O 


221 


1.50 


298 


1.00 


743 


3.30 


136 A 


050 


222 


1.90 


299 


0.75 


748 


2.00 


137A 


50 


223 


3.00 


300 


0.70 


780 


2.50 


I38A 


0.50 


224 


3.00 


302 


1.30 


783 


3.00 


139A 


0.50 


225 


4.50 


306 


1.30 


788 


2.80 


140A 


0.50 


226 


imj 


307 


060 


790 


2.60 


141A 


o.so 


226MP 4.90 


308 


6.80 


791 


2.80 


142A 


0.50 


226A 


1.00 


309 K 


3.20 


801 


2.00 


143A 


0.50 


229 


0.60 


310 


6.50 


807 


320 


144A 


0.50 


230 


4.20 


311 


2.00 


917 


2.90 


145A 


0.50 


231 


3.80 


312 


0.60 


955 M 


1.20 


146A 


0.50 


232 


0.60 


313 


1.90 


977 


1.20 


147A 


0.50 


233 


0.50 


314 


7,50 


1002 


1.30 


148A 


0.50 


234 


0.45 


315 


0.90 


1003 


120 


149A 


050 


235 


1 50 


316 


2.50 


1006 


2.00 


150A 


OSfl 


236 


4.90 


317 


26.00 


100S 


2.15 


151A 


0.50 


237 


2.40 


318 


20.00 


1010 


2,15 


152 


noo 


238 


3.30 


319 


.1.10 


1011 


220 


153 


1.00 


239 


2.70 


321 


3.60 


1014 


2.20 


154 


a 1.40 


241 


2.UU 


322 


1.90 


10 I 5 


2.60 


155 


2.20 


242 


2.00 


323 


2.20 


1016 


2.20 


156 


0.45 


243 


2.10 


324 


2.50 


1019 


1,20 


157 


1.10 


244 


2.20 


32b 


29.20 


1020 


2.90 


158 


0.90 
0.60 
160 


245 
248 
247 


3.00 
4.20 
4.00 


326 
327 
32B 


0,90 
17.00 
9.00 


1024 


4.20 


160 


1Q2S 


161 


0.90 


248 


4.00 


329 


3.70 






162 


460 


249 


/.00 


330 


12.80 


TO 


163A 


5.60 


250 


7.00 


330 W 10.00 


64(W 


164 


3.20 


2b 1 


5.00 


331 


1.90 






165 


130 


252 


7.00 


332 


2.00 


CALL 


166 


0.70 


253 


1.30 


333 


20.00 


FOR 


167 


0.95 


254 


1.50 


:L« 


20.00 






168 


1.00 


257 


i ao 


335 


25.00 


PRtGE 



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1500 TYPES ORIGINAL • 

JAPANESE TRS &, ICS iS 

1000 TYPES ■ 

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OTHER ELECTRONIC 

PARTS FOR TV, STEREO, . 

CB, CAR STEREO V* 



ELECTRONIC PARTS SUPPLY 

TOLL FREE: 800 2270104 

IN CALIFORNIA (415) 532-2711 

P.O. BOX 5356 BERKELEY, 

CALIFORNIA .94705 

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ICRO 
ART 



552 Summit Awe. 

VLUestflekf, NJ. 07090, 

(201 ) 654-6008 



MOTION DETECTOR: Features include transpar- 
ent, optical IC completely assembled on csrcuit 
board with necessary capacitors. Extensive specs 
and application notes included. /$5.00 



CRYSTALS— 3.579545 MHz W, 



JUMBO LED'i 

Green, 7; 1.00- Yellow. 7/1.00-Red, 10/1.00 

100/13.00 100/13.00 100/9,00 

MOUNTING CUPS— 12/1, 00 



7 SEG Displays (comp. grade) 
,3"/95t-.6'7 1.45 (specify ann. or cath.j 



H/FM RADIO CHIP— (#4408) 2 00 or 3/5.00 
Complete AM/FM l&otemal IF required 



DIPPED TANTALUMS 
.47 ).f 35V d" leads) 10/1.00 



SUPER SUB MINI LYTICS 

(1" rad. leads, by Nichicon) 

lOOOnf 50V IIW'L X V. W), 75f or 10/6.00 

47 rt 25V O" L X %" W), 10/(1,00 

400(if 330V (photo flash or laser circuib>>2/1.00 



COMPUTER GRADE TWIST LOCKS 

3200u.f 50V (ideal (or power supplies) 2.00 

lOOOjrf 50V— 1.00 lOOOjif 1S5V-2.00 



DISCS— .001 1KV 25/1.00, .1 50V 15/1.00 



HEAT SENSITIVE SWITCH-^/1 00 
self contained unit opens at 1 50 C 



9 DIGIT FLUORESCENT DISPLAY by NEC 

complete wilh driving circuitry-2.50 



EXTRA LOUD 9V BUZZER— 3/2 00 



WALL PLUG ABAPTIB-5V&C § IgOngjjO 



6.3V 1.2 Amp Transformer— 1 . 7 b 



MINI AUDIO TRANSFORMERS— 3/1.00 



DIGITAL MOTION/UNIT COUNTER MODULE 

(Fairchild) with large 4 digit display & saecs-7.00 



3035 Microprocessor, 17.00 



SUBSCRIPTION TV EDUCATIONAL KIT 

H thare'r i TV dumti *i jtm arid nNch you ran' L tune [a *wj x« l 
a pfowf PKTurE « wind, chjrKn Ire rflu n M*nf i liAscne- 
l»n TV Wfnal. Now jvi can nnd the Usui. Cv 2441(1 MftblM 
mutual conlami a otKrictioA t'- nop si** a yittm wortu, and 
rKlufiai twllnictiw details lor fcuMni J tircjd Iff raitwfl lht 
audio and tridao upiah to thair orwjwi Rita. Our Wt H promt to 
wrkaima.'warrAtoMhaUS by! son rtquri uu. e4 a soatind 
b not EttemSrd (or bc&ntn 

Manual or* ,15 00 

L>aMl««baUKtYOaKt board 23.00 

Board Kid manual . _ 35.00 

ComplcHfat . .. 65.00 



FREQUENCY COUNTER CHIP 
ICM 7225 IPL 

(40 pin), with on board dividers, 
decoders /drivers 13 .95- specs included 



ZENER DIOOES— 20V 1 amp 10/1.00 



INTERFACE CHIP-D8243 
16 line I/O extender for all single chip u Ps 5.75 



TV SATELLITE TRANSISTOR 


MRF 901 (prime) (4-50 




UHEAJt 


IK323K 


100 


WI303 


LalttOI 


.75 


IW1304 


UIM1M 


S3 


ml 305 


UOOW 


SO 


W130? 


LI 307 


31 


W1307( 


UI1MN 


» 


mtaio 


LUXt 


X 


LM1J9I 


LK310 


1.05 


LH1IN 


W311H 


JS 


WHO) 


til 3m 


5.00 


wtss 


waiw 


liS 


LSI 1*30 


IU3IW1S 


1.15 


WI52S 


IV33K-U 


US 


WIB30 


W324 


1-25 


W1WI 


W32S 


1S5 


LallUt 


\Mmi 


1J» 


kMISW 


LU3JCK i: 


125 


Willi 


LM341P42 


IIS 


m:ii3 


W343H 


150 


W2907 


mm 


2JS 


iMsn 


\HM 


2» 


LM3016 


LMSO 


1.15 


IU3054 


UtM 


LK> 


LM30M 


LM3M 


1.85 


1U30S5 


UI3M 


UO 


LU30ST 


mm 


ISO 


uisora 


mm 


US 


LUM7! 


LU74C 


UO 


imxk 


W74SCH 


M 


LM30B 



UO 
95 
1.1} 
JO 
50 
l.IS 
ISO 
2S 
ZJO 
2.7J 
US 
1,75 
IJO 
175 
ITS 
•JO 
ISO 
175 
2.40 
1,95 
1.10 
ISO 
S.00 

:» 

2.50 
2S0 
200 
27S 
1.75 
.75 



Terms MICRO-MART accepts Visa. MC, and telephone COD'S- Foreign orders $50.00 minimum plus 
shipping. US funds only. Orders under $10.00 include $2.00 for shippine/handling. All components 
guaranteed or money refunded. Immediate shipping. N.J. residents add 5* sales tax. 
MICRO-MART « 552 SUMMIT AVE., WESTFIELD, N.J. 070SC > (201) 654^008 



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26-4002 

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$3499.00 



COMPUTER SPECIALISTS 

26-1056 16K Level II System with Keypad $670.00 

26-1145 RS-232 Board 84.00 

26-1140 "O" K Interface 249,00 

26-1141 "16" K Interface 365.00 

26-1142 "32" K Interface 476.00 

26-1 160 Mini Disk • Drive O 424.00 

26-1161 Mini Disk - Additional 424.00 

26-1154 Lineprinter II 720.00 

26-1156 Lineprinter III 1799.00 

26-1180 Voice Synthesiser 339.00 

26-1181 VOXBOX.. 145.00 

26-1104 Factory Upper/Lower 

Case Modifaciion Installed 70.00 

26-1506 Scripsit - Tape 60.00 

26-1563 Scripsit - Disk 85.00 




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DISCOUNT 

Off 



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cEnTRonics 

Fast 100 CPS Centronics 
730 Printer - $675.00 
Text Quality Centronics 
737 Printer - $850.00 



Model II Cobol Compiler 


$360.00 


Cobol Run Time Package 


$36.00 



Novation Cat Modem. .$149.00 
CCA Data Management 

System 72.00 

Adventure Games 

Games 1-9 each 14.00 



S 



Acorn 

Software 
Products, Inc. 



Model I Basic Compiler $180.00 

Model II Basic Compiler 360.00 




BASF 



10-5'/. Diskettes $45.00 

10-8" Diskettes 47.00 



GAMES: 

Alien Invasion $9.00 

Stock Market 9.00 

Star Trek 9.00 

Block 'Em 9.00 

Ting-Tong 9.00 

UTILITIES: 

System Savers 14.00 

EDUCATION: 

Language Teocher 18.00 



•« 



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O 

3 

O 
W 

m 

3J 

[ 1 

139 



rsusaij the first name in Counters ! 



9 DIGITS 600 MHz $129i IPFn 

WIRED 




SPECIFICATIONS 



rrWweU pjrMmKi 


St2»4l 


C T *1 K >l. *0 4t|T F -« i'-" H 






tw.« 


AC- 1 AC titftv 


3.« 


BM Si-.tJ f*tt +-AC 




U irff Ckufcr 


12.M 


OV 1. MlcriV ptitolrt ihjn 




limckfeM 


(I.** 


ErtaTnlal tan* HM WfM 


n« 



The CT-90 is the moll versatile feature packed counter available for let! 
than S 300 .00! Advanced design features include; three selectable gate times, 
nine digits, gate indicator and a unique display hold function which holds the 
displayed count alter the input signal ii removed Alio, a 1 mHz TC XO time 
base is used which enables easy zero beat calibration checks against WWV. 
Optionally: an internal nicad battery pact externa! time base input and M tcro- 
oower high stability crystal oven time base are available. The CT-90, 
performance you can count on! 



Range: 
Sensitivity: 

Resolution: 



Display: 
Time base: 



20 Hz to 600 MHz 

Less than 10 MV to 150 MHz 

Less than 50 MV to 500 MHz 

0.1 Hz (10 MHi range) 

1.0 Hz (60 MHz range) 

10.0 Hi (600 MHi range) 

9 digits 0.4" LED 

Standard- 10.000 mHz, 1.0 ppm 20-40*C. 

Optional Micro-power ovcrHO.l pptn 2(M0*C 

8-15 VAC® 250 m> 




7 DIGITS 525 MHz $99f IRED 

The CT-70 breaks the price barrier on lab quality frequency counters 
Deluxe features such as; three frequency ranges - each with pre- amplification. 
dual selectable gate times, and gate activity indication make measure merit 5 a 
map. The wide frequency range enables you to accurately measure signals 
from audio thru UHF with , .0 pprn accuracy- that's ,0001%! The CT-70 is 
the answer to ail your measure mem needs, in the Held, lab or ham shack. 



SPFC1FFCATIONS: 


Range: 


20 Hz to 525 MHi 


Sensitivity: 


Less limn 50 MV 10 1 50 MHi 




Lass than 1 50 MV to 500 MHz 


Resolution: 


1.0 Hz(5 MHz range) 




10.0 Hz (50 MHi range) 




100,0 Hi (500 MHz range) 


Display: 


7 digits 0.4" LED 


Time base: 


1.0 pptn TCXO 20-40'C 


Power 


12 VAC 9 250 ma 



PRICES: 




CT-70 wired, 1 year warranty 


S99.95 


CT-70 Kit. 90 day parts war- 




runty 


81.95 


AC-1 AC adapter 


3.95 


BP-1 Nicad pack + AC 




adapter/charger 


12.95 




7 DIGITS 500 MHz $7951 

WIRED 



PRICES: 

WIKH00 wired I year 

warranty $79,95 

MINI-I00 Kit, 90 day part 

warranty 59.95 

AC- Z Ac juJapu r for MINT- 

100 3.95 

BP-Z Nicad pack and AC 

adapter/charger 12,95 



Here's a handy, general purpose counter that provides most counter 
functions at an unbelievable price. The M1NI-I00 doesn't have the full 
frequency range or input impedance qualities found in higher price units* hut 
for basic RF signal measurements, it can't be beat! Accurate measurements 
can be made from 1 MHz all the way up to500 MHz with excellent sensitivity 
throughout the range, and the two gate times let you select the resolution 
desired Add the nicad pack option and the M IN I- 100 makes an ideal addition 
to your tool box for "in- the- fie Id" frequency checks and repairs. 



SPECIFICATIONS 


Range 


1 MHz to 500 MHi 


Sensitivity: 


Less than 25 MV 


Resolution: 


100 Hi (slow gate) 




1.0 KHz (fast gate) 


Display: 


7 digits, 0,4" LED 


Time base: 


2.0 ppm 20-40* C 


Power. 


5 VDC ® 200 ma 





8 DIGITS 600 MHz $159^ TDT3n 

WIRED 

SPECIFICATIONS: 

Range: 20 Hi to 600 MHi The CT-50 is 1 versatile lab be nch counter that will measure up to 6 00 MHz 

Sensitivity: Less than 25 mv to 1 50 MHz with g ai ^ t precision. And. one of its best features is the Receive Frequency 

Less than 150 mv to 600 MHz aj,™, which „„,, Ae CT .jo „„ , A m u \ readout for any receiver. The 

1 .0 Hz (60 MHz range) ., . , , , ,. 

100 H I f*00 uujra adapter i s easily programmed for any recei ver and a simple connection to the 

8 digits Q 4" LED receiver 5 s \T O is all that is required for use. Adding the receiver adapter in no 

2.0 ppm 2O-40*C w> y limits the operation of the CT-50, the adapter can be conveniently 

1 10 VAC or 1 2 VDC switched on or off The CT-50. a counter that can work double- duty- 



Resolution: 



PRICES: 




CT-50 wired, I year warranty 


$159.95 


CT-50 Kil, 90 day parts 




warranty 


119-95 


RA 1 . receiver adapter kit 


14.95 


RA-I wired and pre-program- 




med (send copy of receiver 




schematic) 


29.95 



DIGITAL MULTIMETER $99f IRED 




PRICES: 




DM700 wired 1 yearwamnty 


S9O.05 


DM-7O0 Kit, 90 day parts 




warranty 


79.95 


AC-1, AC adaptor 


3.95 


BP-3. Nicad pack +AC 




adapter/ charger 


19.95 


MP-1, Probe tit 


2,95 



The DM -700 offers professional quality performance ar a hobbyist price. 
Features, includes 26 JstYcrcnr range* and 5 function** ill arranged in a 
coiwenirni, eisv to use format. Measurements arc displayed on. a large 3!^ 
cbfrr. H inch LED readout with automatic decimal placement, automatic 
polarity, overrange indication and overload protection up to 1250 volts on all 
Nin^es, making it Virtually tpLKif- proof! The DM- 700 looks Ere.it . a handsome. 
Jet black, rugged ABS case with convenient retractable tilt bait makes it an 
ideal addition to any shop. 



SPECIFICATIONS: 
DC/ AC volts lOOuVtol 
DC/ AC 



KV h 5 ranges 



current 

Resistance: 

Input 

impedance 

Accuracy; 

Power 



A uA to 2,0 Amps, 5 ranges 

0.1 ohms to 20 Megohms, 6 ranges 

10 Megohms, DC/ AC volts 
10,1% basic DC volia 
4 'C cells 



S 

2 
O 

£ 



O 

a 



AUDIO SCALER 

For high resolution audio measurements, multiplies 
UP in frequency. 

• Great for PL tones 

• Multiplies by 10 or 100 

• 0.01 Hi resolution 1 
S29.95 Kit S39.95 Wired 



ACCESSORIES 

Telescopic whip antenna - BNC plug ......,., S 7.95 

High impedance probe, light loading 15,95 

Low pass probe, for audio measurements , J5-95 

Direct probe, general purpose usage . . . . . . ... 1 2.95 

Tilt bail for CT 70, 90, MINI-LOO 3.95 

Color bunt calibration unit, calibrates counter 

against color TV signal *.*..,*... . 14,95 



COUNTER PREAMP 

For measuring extremely weak signals from 10 to 1,000 
MHl Small sue. powered by plug tranaformer'included. 

• Flat 25 db gain 

• BNC Connectors 

• Great for sniffing RF with pick-up bop 

S34.95 Kit £44,95 Wired 



n iiy!i, .1; .m li .%. in. 



BOX 4072 



ROCHESTER. NY 14dl0 



PHONE ORDERS 
CALL 716-586-3950 



■•fa rid Add f!% fat ihi 
...... cU 10 Cwncnodd l 5 COD add 

*ind*i i 10 add 1 SI 50 Nv Wtdtf.1i odd 7 '■a Teai. 



140 



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POWER SUPPLY KIT 

* U5V/2SV CT tr«rm£of»«rd 1- 
UnHftT and J-LnlSOT r^u 1* to r ■ 
Uh iUMIily th* above <rt>lt*g*ft, 
K»t link provided for +3v 
PAWS INCLUDED 

■PC ba-ird 

4 diode* 

CApAcltcr 10 00 ttC 
C *;i* c - "- -3 r 500 r 
3 Capacitor* ID uf 



DISCRETE LED'S 




10-24 
25- 



S14.95ea 
13.50ea 
12.50ea 



JUH80 LED 

.20"dii, diffused 
Bed, dear or KM te 
Green or Vellw 

StlBHlNITUffi LEO 
.12b"cJia. diffused 
Bed or Clear 
Green or Yellow 



10/51.00 25/S2.00 100/(7. SO 
7/S1.00 2S/S2.85 100/S9.7S 



10/ SI. 00 25/ 52.00 10O/S7.50 
7/S1.00 25/S2.S5 1O0/S9.75 



LED DISPLAYS 



DIODES 

IN4148 [1N914) 4005K I5/S1.00 10O/S5.0O 1000/S40.0D 
IN" 001 SOP IV 12/ SI. 00 100/S7.00 1000/560.00 

1N4007 looopiv io/si.25 100/511.00 1000/sio.oo 







.4" ORANGE LED DISPLAY 

7 segment RHD 
MAN461D - comqon anode 
MAN4640 - coninon cathode 

4" ORANGE overflow +1 

MAN4630 - coimton anode 



.3" RED LED DISPLAY 
7 segment RHD 

fcAN72(MAN72 equiv) 
common anode 

.3" RED LED DISPLAY 

7 segment RHD 
N5N74R common cathode 



.6" RED LED DISPLAY 

, 7 segment LHD 
XAN6340 - common cathode 



$1.1 9ea 
10/17.95 
25/517.50 
100/ $65. 00 

S.89ea 
10/J5.P5 

S.99ea 
10/17.95 
25/117.50 
100/$65.00 

$.79ea 
W$6.95 
25/J16.25 
10O/$59.0O 

$1.25ea 
10/111.50 
25/526.50 
100/ $98. 00 



TRANSISTORS 

2N39D4 NPN 10-92 S.2Sea 10/S1.65 2S/S3.Z5 1D0/S12.O0 

21(3906 PNP 10-9? S.25ea ID/51.65 25/ 53,25 100/S12.00 

2N2222A KPN TO-18 S.45ea 10/53.50 2S/S8.00 100/(29. SO 



DIPSWITCH - 4 SW 
8 pin DIP SPST 
1-9 $1.65ea 
10-24 1.55ea 
25- 1 .49ea 

DIPSyiTCH - 8 sw 

16 pin DIP SPST 

1-9 $2.10ea 

10-24 1.95ea 

25- 1 .85ea 



ew 



DIPSWITCH - 10 sw 

20 pin DIP SPST 

1-9 $2.20ea 

10-25 2.05ea 

25- 1 ,95ea 



LINEAR CIRCUITS 



1/? PRICE SALE 

REG. SALE 
$.59 

3: 



CERAMIC CAPACITORS 

56pf 120pf 270pf 



Ipf 
5pf ■ 
7pf 
IDpf 
Ipf - 
Total ' 
1-100O 
1000- 



2Zpf 

27pf 68pf 
33pf 82pf 
47pf- lOOpf 
.050 of 

EA. PK-10 
$.20 1.00 

.20 .85 



120pf 
ISQpf 
ISOpf 
220pf 



390pf .001 uf 
470pf .0015uf 
600pf .003iif 
-luf 
PK-100 EA. PK-10 
6.50 .25 1.25 

6.00 .25 1.10 



.O047of 
• Oluf 
.015uf 
,022uf 

PK-100 

9.00 
8.00 



.030uf 
-OSOuf 

.luf 



CERAMIC CAPACITOR KIT 

CK-C2 Sea. of the above values $11.50 

CK-c.3 lOea. of the above values 20,50 




UNIVERSAL BREADBOARD 

IC BREADBOARD SI .OOea 

10-24 .90ea 

25-99 .SOea 

100- ,65ea 



POLYESTER FILM CAPACITORS - 100V * 
EA. PK-10 PK-100 



' .OOluf $.15 

.OOlSuf" .15 

.0O22uf .15 

.0O33uf .15 

»•.*0M7u^'•>fT5* , 

,006Suf .15 

-]5. 

.16 

.15 



'*»*:^3uf 



.022uf 



.95 
.95 
.95 
.95 
.96 
.95 
.95 
.95 
.95 



10% 

EA, 

1.20 

.20 

.25 

30 



PK-10 
6.50 .033uf S.20 1.00 
7. SO ,047uf .20 1.15 
7.50 .068uf .25 1.30 
7,50 .luf .30 1.75 

7. c ,ft ,15uf .35 2.25 



• TOTAL OTYi 1000 pes 



7.50 
7.50 
7.50 
7.50 
-lOt, 



.22uf 
,33uf 
.47uf 



.40 

.45 
.50 



PK-100 
10.00 
10,50 
12,00 
13.50 
14.00 
20.00 
25.00 
30.00 



5000 pes. -151 



PaY ESTER CAPACITOR KIT 

5 ea of the above values $14.95 



TANTALUM CAPACITORS 

solid dipped ± 20)! 



■ tr*» 



Huf/asv 

,22uf/35V 

,33uf/35V 

luf/SOv 

I.Suf/ZtW 

2.2uf/20V 

2.2uf/35V 

3.3uf/35V 



.30 


.26 


.30 


.25 


.30 


.25 


.30 


.25 


.30 


.25 


.35 


.25 


.'38 


.28 


.40 


.30 



4.7uf/16V 

4.7uf/25V 

S,8uf/6V 

6.8uf/l«V 

lOuf/ZOY 

15uf/6V 

15u>f/20V 



.38 
.45 
.35 

.45 
.42 
,42 
.50 



.30 
.35 
.28 
.39 
.35 
.35 
.40 



22uf/16V 

22uf/35V 

33uf/6V 

33uf/10V . 

47uf/6V 

47uf/15V 

56uf/6V 



.50 
.60 
.55 
.60 
.60 
,55 
.35 



.40 
.55 

.45 
.50 
.50 
.55 
.75 



CAPACITOR KIT 
tantalum 



ck-t2 



salifl aippetf i20t 



.22uf/3S1 
luf /35V 



2.2ur/Ji\ 
],Jaf/JSV 



S.Suf/16V 

I Cut/Mi 



»>«/ltv 

33uf/IW 
Uatftm 



Sti of above T*luei ................. (17.75 

SKwIted tn tit*r ityrtne utility box........... ,.....(tl;K 



LH300B 

LH301CII 

LM302H 

LM307CN 

LH308» 

LK30SCK 

LM309H 

LH31CU 

LM311H 

LM31ICH 

LM31 IN 

LM32ZH 

LH340T-6V 

(7806) 
LH37ECN 

LHseo-s 

L15S5N 
LH709H 
L.M73JH 
LH739N 
LH748CN 
LM414N 
LH1S0OH 
75453CN 
(3SICN) 
75491N 
7S492N 



,S9 
.32 
.79 
.79 
l.OS 
1.07 
.89 
.89 
.89 
.89 

1.19 

.50 
,B9 
LIS 
.39 
.89 
.89 

.a 
i. is 

!.40 



(.30 
.16 
.30 
.18 
.40 
.40 
.53 
.54 
.45 
.46 
.45 
.45 

.80 
.25 
.45 
.53 
.20 
.46 
.45 
.18 
.63 
1.20 

.18 
.38 
.45 



TrL 

7400 (.18 

7401 .18 

7402 .18 

7403 .18 
740* .20 

7405 .25 

7406 .20 

7407 .20 

7408 .27 

7409 .27 

7410 .18 



7415 
7416 



7417 .20 
7420 .20 



7425 
7426 
7427 

7430 
7432 



7437 .20 

7438 .18 
7440 .18 

74*1 .59 

7442 .35 

7443 .55 

7444 . 60 

7445 .50 

7446 .59 
7448 .59 

7450 .18 

7451 .22 

7453 .IB 

7454 .18 
7460 .18 



7464 

7465 

7470 

7472 

7474 

7475 

7576 

7480 

7482 

7483 

7485 

7486 

7489 

7490 

7491 

7492 

7493 

7494 

7495 

7496 

74105 

74107 

74121 

74122 

74123 

74125 

74126 

74132 

74141 

74145 

74148 

74150 

74151 

74153 

74154 



.30 
.30 
.49 
.32 
.18 
.49 
.49 
.35 
.25 
.58 
.50 
.42 

1.75 
.59 
.64 
.S9 
.35 
.59 
,3S 
.35 
.48 
.35 
.35 
.39 
.39 
.50 
.50 
.75 
.36 
.50 

1.26 

1.35 
.50 
.35 

1.45 



74155 
74158 
74157 
74158 
74160 
74161 
74162 
74163 
74164 
74166 
74170 



.50 
.64 
.60 
.75 
.70 
.79 
.85 
.35 
.85 
.85 
1.50 



74173 1.26 

74174 1.05 
7*175 .85 

74176 .70 

74177 .70 

74180 .35 

74181 1.85 

74182 ,35 

74189 .50 

74190 1.15 

74191 1.15 

74192 ,50 



74193 
74194 

7*195 
74196 

74197 
7*198 



.79 

.85 
.69 

.80 
.75 
1.40 



74199 1.25 
745200 3. 75 
74279 ,65 



8000 (Signet ki) 
S263 2.95 8267. 

9000 Series 
9601 .25 9602 

CMOS 

4000 Series CMOS 



1 . 75 8281 



4000 (.25 

4001 .39 



4002 
4006 
4007 
4008 
4009 
4010 
4011 
4012 
4013 
4014 
4015 
4016 



.25 
.95 
.39 
.95 

.46 
.:.', 
.'5 
.25 
.5? 
.95 

:,\ 

.64 



4017 1.08 

4018 .95 



4O20 
4021 
4022 
4023 

4024 
4026 
4027 
4028 
4030 
4035 
4040 
4041 
4D42 
4043 
4046 
4049 



1.14 
.95 
.95 
.30 
.75 
.22 
.59 
.86 
.49 
.95 

1,15 

1.20 
.95 
.85 

1.69 
.45 



4050 .45 

4051 1.15 



4066 
4059 

4071 
4072 
4073 
4078 
4081 
4082 



,79 
.39 
,29 
.39 
.39 
.39 
.39 
.30 



4618 1.2S 

4528 1.50 

4585 1.50 

*901 .59 



IMMEDIATE DELIVER! OP QUALITY RESISTORS 



CARBON FILM RESISTORS 

CARBON FILH i5* t0tJ ' 2S" t1W « \l 

l/4witt (R.OM R25) ™ 3 *'\n 

,095"dfa X ,250"long (My) i£$ 

l/2uatt (B.Ohn R50) 

.!46"dfi I ,354 "long (body) 

25 or more resistors 



10000- 



. 10 
.10 



PRICING 1/4 £ 1/2 watt 

ttt-10 Pd-100 pk-1000 

.46 2.00 

.40 1.80 15.00 

.30 1.70 14.50 

.i5 1.55 13.00 

not individually packaged - 



VALUES STOCKED (ohms) mined - specify any assortment of values S.04e» 



3.9 

4.3 

4.7 

5.1 

5.6 

6.2 

6.8 

7.5 

8.2 

9.1 

10 

11 

12 

13 

15 



68 
75 

s; 
81 

100 
110 
120 
130 
ISO 

:6o 

ISO 

?cc 

220 

: U 
270 



300 

330 

360 

390 

430 

470 

510 

560 

620 

680 

750 

820 

910 

I. OK 

I.IK 



1.2K 
1.3K 
1.5K 
1.6K 
l.M 
2. OK 
2.2K 
2.4K 
2.7K 
3. OK 
3.3K 
3.6K 
3.9K 
4.3K 
4.7K 



5. IK 

5.6K 

6.2K 

6.BK 

7.5K 

S.2K 

9. IK 

10K 

IK. 

12K 

13K 

15K 

16K 

181! 

20 K 



22K 

24 K 
271 

soi 

33K 

36. 
39K 

43K 
47K 
51 « 
56K 

68K 

■it 
82K 



91K 

iooi: 

110K 
120K 
130K 

150K 
160K 
ISO): 
200K 
220K 
240K 
270i: 
300K 
330 K 
360K 



390K 
430K 
470K 

510K 
S60K 
620K 
630K 
750K 
820K 
91 OK 
1.0H 
1.1M 
1.2H 
1.3M 
1.5M 



l.Wt 
1.8M 
2. ON 
2.2K 
2.4K 
2.7H 
3, OH 
3.3X 
3.6H 
3.9)1 
4.3M 
4.7H 
5. IN 
5.6N 



•6.2N 
'6.8M 

•7.5M 
•8.2M 
«9.]N 

■ion 

■11H 
•12H 

*13M 
•15M 
I* 1/2* 

only) 



fovliw 

nuunt miMMMltr 



NETAL FILM IIS 

RN60 (B.Ohm CRB60FY) l/1*att 

Low temp coef - SOppp/^ I 

.138'dia I .J55"long (tody) 

color bended 



METAL FILM RESISTORS 

total quantity 



ELECTRONIC 3LZZER 
6V or 12V S1.25ea 
10-24 l.OOea 
25- ,90ea 



Standard 1* 



10,0 
10.2 
10.5 
10.7 
11.0 
11.3 
11.5 
11.8 



12.1 
12.4 
12.7 

13.0 
13.3 
13.7 
14. Q 
14.3 



14.7 
15.0 
15,4 
15,8 
16.2 
16.5 
16.9 
7.4 



pk-10 pfc-25 pk-100 pk-250 
1-999 S.25 1.00 2.00 7.50 17.50 

1000- ,20 .90 5. BO 7.00 16.25 

5000- .20 .85 1.70 6,50 15.00 

10000- .20 .80 1.55 6.00 13.75 

10 or more resistors - not individually packaged - 
mixed - specify any assortment of values S.lSea 

VALUES STOCKED (ohms) 

metal film values from 10 onm to 475K ohm 

17. B 22.6 27.4 33.2 40.2 4B.7 59.0 71.5 B8.7 

IB. 2 23.2 28.0 34.0 *1.2 49.9 60.4 73.2 90.9 

IB. 7 23.7 28.7 34.8 42.2 51.1 61.9 75.0 93.1 

19.1 24.3 29.4 35.7 43.2 52.3 63.4 76.8 95.3 

19.6 24.9 30.1 36.5 44-2 53.6 64.9 80.6 97.6 

20.0 25.5 30,9 37.4 45.3 54.9 66. S 82. S 
20.5 26.1 31.6 3E.3 46.4 56.2 68.1 84.5 

22.1 26.7 32.4 39.2 47.5 57.6 69.8 86.6 



f}»/IUI 



and mul til pies of 10 of the above values to 475K 
i.e. 10.0 100 1,0k 10. OK 100K etc (total 4481 



o 
o 

(S 

m 

31 

03 
CO 

© 
141 



Payment by check, H.O. , UPS/COD, M/C or VISA. Add $1.00 for 
shipping/handling in J S, Canada and Mexico. Additional charge 
for UPS COD 6r BLUE LABLE, Other Countries II. 00 + 5* of order 
total. California residents add sales tax. Minimum order 110.00 

SCHOOLS AND GOVERNMENT ORDERS ACCEPTED ON OFFICIAL 

PURCHASE ORDERS, 



INTERNATIONAL ELECTRONICS UNLIMITED 



225 Broadway Oackson Ca 
phone 209 223 3870 



95642 



CIRCLE 48 ON FREE INFORMATION CARD 



g 

Q 
< 

142 



7400 



5N740ON 
SNF4C1N 
SMfJOJH 
SN74Q3H 

5NH05N 

5Nf4C7H 
SNrJOflN 
SNMOflN 

SSiMiUi 

SN7414N 
3H74tflH 

SN74I7N 
SN742QW 
5N7421N 
5N7422N 
SN7473N 
SnT7425N 
SNT420N 
SN741T7N 
SN742SH 
SN743QN 
SMr4i2H 
SH7437N 
SN743AN 
SMMMN 

S^744>N 

S«-**4JH 

SNMt&hi 

5*17*47^ 
S»744fth 
SMT4S0JI 

9M74&1H 
8W74SJM 
SH7494N 
5H74&QN 
5PIT460W 
SHT47oM 
5H74T2M 
SN7473W 
SNT474H 
SH747BH 
$H7*7GH 
SNT47BW 

SH;4#Qhr 

5*740 IN 
S*fr4B?N 

5NT4-B3N. 
SNMfl&N 
■Vj.'-!!..-, 
5W749SW 
3NJ4B0N 

SH746JP4 

SHT4.MH 
SN74B5N 

SH74M» 
SN74Q7H 

SNrVroo* 

SH74107W 
ShT4tMW 
5N7411IUJ 
SNT4I21-H 
SH7412JN 



5K7412JM 
SW412-W 
3*774 12*N 
6N7412HN 
SW413JN 

K'l.Mljri-.j 

6*74 139N 
3*»74HiH 
SW414JM 
BH74t43N 

5W74143N 
SN7414IN 
3H7414GM 
5N741MM 
3H74151N 
3M741S2N 
SN741S3H 
5N741S4H 
SN741B6H 
SHT41MW 
3H74167N 
■,.',:-:>■ ■■■• 
■.t\:-:u''\ 
SH74ifliN 
3N741MN 
SHT41&3*) 
SN741VH 
SNT41G6N 
3N74l8*H 
SN7«107« 
SH74WCM 
SW74173N 
3N74173N 
3N74174N 
SH74U3M 
SW7417I1W 
SW4D7H 
SNM17&N 

W4iaiH 

SHT4163I* 
5H741WW 
5N741S5*« 
SH741WW 
5U741M* 
SN7419GW 
SH74191N 
&J74192N 
&M74133W 
SN741S4N 
SN741MH 
SN741B0N 
SH741B7H 
SH741BBH 
SN7*lMN 
SW74221W 
SN74SS1N 

swT-4jr3hr 

SH7437D* 
&N74J&3H 
SH74264N 
SM74J6SW 
SH74JSW 
BK74SBAN 
W*36&n: 
6NT43CGM 
&M74367** 
SNr43$aN 
MTWOH 
WT4W3H 
BKM49QN 



£10 
9 BO 
UO 

' "- 



CMOS 



CWCCQ 
CD4O01 
CO40Q2 



C&tfl-lO 
CD+D1 I 

co*oi3 

CD4Q13. 
CD4014 
CD4D1i 
CP4D16 
E&AOW 
CD401A 
CD4010 
GD40Sa 
CD4A31 

CCM024 
COW25 
CD*&27 
CD4DJ0 
CD*DZ9 
CCM&.30 
C&4031 
CD4D3J 
COA03-4 
CD*D3i 
CD4M.I 

CD4Q40 

£0*041 
CD4CH7 
CD4C-41 

CD4&I4 

C04W6 
CD404/ 
CD404A 

CD4W* 

C&HMfi. 
Cl>i9V 
CD4&W 
CD4C*i 

CD4f>U 
CD4LW. 

CQ4EK0 
CD 4«">, «-, 
CQ4WA 
CUW> 
CD407I 
CfM07? 
GEMOTS 
CD40T5 
C&40U, 
C04Q77 
014071 
C04C*« 
CO4O02 



■ ' P 

143 

' £9 



2.1A 
3?5 



CO4093 
CD40B4 
C04O0H 

CO400B 

UC1441D 
UC144I3 
MCT441S 

MO 441 B 
CD45CI 

CD4»! 
CD4»3 
CCM»5 
CD45QB 
CD4»7 
CD4-MB 
CCMilO 
CDJ51 I 
QD45U 
CD4315 
CD441S 
CD4510 
CD4520 
C&4SM 

CD45M 

74C00 

T4QJ3- 

74C04 

74HW 

?*C1Q 

74C14 

74CM 

r4tii 

74t47 

MUI 

r*Oa 

F4C.74 

r4ct% 

74Uf 
I-4C90 

r4di 

74»* 
?4C107 
F4C1S1 
74C1M 
74C1»7 
W-i« 
74C1A1 

HCtra 

74C1IM 
74C173 
T4CW4 
74C1 75 
74C19? 
7*C191 
74C1D4 
74C822 
F4CS33 
MMS0C9& 

-"■ : ■• 



99 
295 
240 
225 
1295 
1295 
1295 
1295 
SS5 
495 

1« 






t4S 

•i H 
3.10 
2Jfi 
..' M 
1 31 
:■ h 
a m 

. ■ 

:■ h 
rjfl 

■ H 



74LS00 



74L5GON 

74LS0TN 
74LS02N 
F4LS03N 
74LSCHN 
74LS05N 

.'4I..S07N 

74LSXON 

r*UiiH 

74SJt2N 

74tS>3N 
74L5T4M 
74LS>5M 
74LS20M 
74L521H 
7«L5i22H 
74L53XUI 
74L527M 

7*L5aaN 



7ALS33H 
74LS37W 
7*LS3aN 
74LS40I4 
74L342K 
74LS47N 



74L5dWW 
74LSiaW 
74LS1EAN 
74LS1UM 

74LS169N 
74LS»70N 
74lSt73H 
74LS174N 
74LSI75N 
74LS(B1N 
74LSIDON 
74LSlBtN 
/4LSi»2^ 
741S1 93*il 
741S1B4N 
74tSlB5H 
r4tSl*W 
74LS1S7M 
74UJJ1N 
F4LSW0N 
74L5241H 
74LS245H 
74LSS43N 
74L5244H 
7tLSS4GM 
74LB247N 
7*LSZ4fln 




3 H 

Ha 



WLS51N 
'4U94N 
74LS56h 
74LS73H 
74LS74N 
74U.7JN: 
74US76W 
TALSTfiW 
r4UJBSiW 
T4US8SH 
74LSHH 
74U3S0H 
74L392H 
74L5«N 
74L5H5H 
74L596M 
74LS1D7N 
74L51WN 
74LSH2H 
74LS1 13H 
'* LS 1 14K 
74LS122N 
74151 Z3H 
74L5124H 
74L512&N 
74LS12SN 
74LSI32N 
74LS134H 
74l.SJ.3BH 
74LS139N 
74LS14&N 
74tSt4«N 
74LSU1N 
74LS1UN 
74L81S4N 
74L5I55N 
74LS15CN 
74L5157N 
741SI5BN 
74LS1QON 
74L31&1N 
74LS1C2N 
74LSIE3N 



7JLS2-51H 
74LS253M 

74LS257N 
74LSa5HNj 
r^LSMBN 

r4LS?fliw 

?4LS?66K 

74LS273W 

74L337SN 

MLSZTON 

74L3383K 

74LSJO0IV 

741,SM3hr 

r«L83BSN 

74LSJMH 

74LS324N' 

741.S347H; 

74LS34BN 

74USJWW 

74LSJ53H 

74LS363H 

74LS365H; 

74LS36BN 

74LS367N 

74LS3BflN 

7+LS373N 

74LS374H. 

74LS37BN 

T+LS377N 

74LS3B5H 

f4LS3flBH 

r4jL&3HH 

74L5383H 

f4tS3BSH 

74LS3BBH 

74LS4J4H 

74LSWDN 

74LS670H 

5ILS35H 

fi1LS»H 

AILSS7N 

B1LJHHN 



I 10 
i H 

1 70 

I H 

1.75 
1 39 

! H 



LINEAR 



ranofl 



5BS 



7BM& 

LM1UH 
LU10QAH 

LU3D0H 

LUJ04H 

LM305H 
UWJ06B 

LM307CI*M 

LMj«K l 4ft 

LUJipQH 1JS 
LM311D.-CN* «& 

tWtJISM 17S 

l.WJin 27S 

LMJiBCN'M 1 ift 

LM31BNVH l 25 
LU330K-»t* 
LMK07-1O? 

LM3J4N 
LM333H 
LU34CIKW 
LM3407-J(K' 

LM340M-XX" 

LMJ44H 

LW34BN 



1.4B 



:--m 



33£ 



1.40 
1» 

4B4 

115 



LM3CQN 
LM372N 
LM37DN 
LW377H 

iwaeco^H 

i.**MlN 
LM303T 
IM3B6N 

IM3B7H 

HBsn ■ 

NESSflV 

HEM 11 

HE»se 

HEM4N.-H 
HCJMK-V 

'.■■'.■v-V M 

■LM.r«H 

LM7«H/H 

LMfiOW-H 

UM711^>M 

LM715N 

LM753N'H 

LM7i3R>H 

LU741CN,tf 

LM741CN-14 

LU747K*1 

LM.'iSN ft 

LM7BDCN 

tM1310t< 



H 

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rje 
1 ts 

i rs 

■ ., 

3 *fl 

Ut 

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LM1414H 1BO 

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MC1406N 

MC14B9N 

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I.M.15M-H 

IM100CN 

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UC34J3H 
MC3*&3H 
SOU24N 
CAJCOON 
LMMOOh 
LO3909N 



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395 



2H 
2 95 

229 



1 M 

4JH 
■ 41 
I H 

: 68 



isi 

JJB 

2 49 

1 95 

2 49 

2 40 

3 49 



US 

1 H 



RC4131H 

RC4130N 

FIC4151N 

RC4194 

BC4195 

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uttiiiMJ 

SH7545CN 

SN75451N 

SN75452N 

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SH7549IN 

SttT/EMaiN 

SNTMMN 

SNfi4S4H 



.■ K 
1.10 
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1 




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■MU XI1 &i>LM CJpRtKn Uttff 

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H,U S5* BBC UKLr HntWCI Fitajii^ Cortp- 

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?7500 
F9SC0 
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60 oa 

14700 
IKM 
3fi00O 
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BKLB 

7700 

2195 



Apple II.16K 

or Apple II. Plus $990 



16K Apple Upgrade Kit S62.95 



Hi-5pced Swu vo 


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?7900 
25000 


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4G35 00 



A ATARI" soo & 400 

Personal Computer System 

ATARI SOO $750.00 
ATARI 400 S449.O0 

ATARI BOO Include*: Compuier Console, BASIC Long. Carrndge. Education 
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Manual w/Nalebook Abiri 410 Progfem Record-flr flK RAM Module, Power 
Supoly, TV Swilch Box 




Hi) 






!:-:« 




]}» 


■a 






fiK- 




i).>: 


31K 


lAV: Cjt> Tn^mw. 


■ IK 


]■;:■:■ 






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HhUlb^UqUt 


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ihMMUnnUiu 




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AM 


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HOI 


AMMPlh**T 
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MX 


MM 


nuHCiMiMltn 


ll-M 




Texas Instruments 

I^CIIHPIIRAI | D 

99/4 PERSONAL COMPUTER 

Superior Color,. Music, Sound and Graphics -and a 
Powerful Extended Basic - All Buill in. 

Tl 99/.', Console only 

available for $638.90 



$1099.00 



fz: commodore 
PET ^ M $775.00 

CHSCOUHT PRICES LUW *" 



f'!-S 


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mn 


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CRAIG LANGUAGE 

TRANSLATOR AND 

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An luttiil IT jn-fiilc-' 

of wsrdi and 

ptwaMa from i'ho 
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QLUqBrS (Ajl * iam 

function ealeuiniOr 
plul irrJomtAlton 

bamPdiM>ne 
guJe. wt 

speciAtuow price ^^^^r s ftC 

fUNTIL AUGUST 17] 
PLUS »20.00 REBATE FROM CRAIG 

CfiAJG MODULES AVAILABLE FROM 324 95 




The IfiermojEal iftil uses m^icroprotH ssor 
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PROGRAMMABLE ',, ^^_ 

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CONTROLLER 

ACP PRICE 

$69.95 

A lully aulomalic electron ic Ihefmo. 
slat. Easy to Install and operate. 
Compare the cost; TPI's temperature 
controller Is the lowest priced elec- 
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SINGLE BOARD COMPUTER SELECTION GUIDE 



BOA no 

KIM-t 

SYM-1 

Cromemcc 
SD-SBC100 
AIM 65 
Cosmao VIp 



PHOCESSOR 

6502 
6502 

Z80 

ZBO 
6502 
1802 



ACP PfllCE 
169.00 

235 00 
400.00 
239.00 
375.00 

199.00 



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Add 29.95 

Add 39 95 

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KM 

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Inc 



P.O. Box 17329 Irvine, Calif. 9271 3 

Direct Order Lines: (714) 558-8813 

(800) 854-8230 or (800) 854-8241 



FOR INTERNATIONAL ORDERS: 
1401 E. Bore hard (714| 953-ufsOi 
Santa Ana. CA 927 05 TWX: 91 0-595-1565 



CIRCLE S ON FREE INFORMATION CARD 



v-zIadsanced 1 
t z>-computer 

^MODUCTS 



■ ESUSf I it.1 ' fr.T.l il »fe jH 



>rW*/ 



• s-1 oo azK (uses z 1 1 4) 

Kii i*"* 

450ns, 468.00 
250ns. 499.00 



ASSEMBLED 
450ni. 498.00 

250ns. 539.00 

Bare Board 49.95 

Bare Board w/all oaris iess mem 99.85 



• S-1QO 1BK |S-1 00 Compatible) 

• 2^1™ 4 MHl Uf OWf ■ 

• Assembled S Tested 
2MHj.MS0.00 
4 MHz . S285.00 



.sSemb'lId 



KIT 45Qns 1Z595 
250ns 169.95 250ns 143 95 

aste PC Board w/Daia S2l 95 
'So-SOa! Otter' Buy J4lflKdS0*.5 Kits Si I TOO 



Til* VIST* V-80 

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ATTENTION VIDEO HOBBYISTS!!! 

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•.<* $74.95 

pjoaso Caff F or VefunM tOiscoimts 





LOW COST FLOPPY 
DISK SUBSYSTEM 



srwasn «1R Oimj rj| viSTft Ffespp* 
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SAVE 5300.00 |S 1 799.00 Value) 



WATANABE M IP LOT 



/7T 



8K Staltc 

16K Sralir: 
32K Staiic 



E50 na. 450 ns. 

S209.00 £189.00 

S4 49.00 5399.00 

£729.00 £629.00 



ANADEX PRINTER N f *.»r E .f.uo* 

Model DP-S000 compaGl, impact, parallel or 
serial. Sprocket teed. 60 cote. 

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New only 5875.00 

pf^SOOQAP {for Appte)S875 r OO 



^tsfl SO SYSTEMS BOARDS 

S* w TAKE 10% OFF! nt asmm 

SBC 100 &rfll* Board CanWt r2MHl| 379900 V 3-U DO 

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ZKh3«H*iSrH»" ltf« 441900 

VtJflB074 VdB-3 QocU,- hWO 33iHl 44900 

WrH-fiiCT, M 57500 42900 

EttuiA PfirZW MS 00 HJtfl 

SOlMCort6y1ti'&(»l"i"*l**f. " 9933 00 

50200 Cwx>Ji» r SrWij"' h. 44 «L - W1M 



i.'-:r-! . 
9WM 

ten 

swi 
kg* 

9M3 
S6Q4 

940$ 
0610 



££ 



MICROMODULE • PRICE 

WO 0E3CR1PTKJN 

S- "c * &s*'fl V*'&M>ripijlflr- 
ArJiiVNTCd SrtQ>t Bd Comp lfl«K 
IB SAM MS'C' Bo*'d 

amcw 

a &t: MWnen Ebitrf 
Pe*Tf Swcoiy 

DC Ir-fr^l POw4' SofJC^T 

Uiii-Ey P-«n Board 

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6vH»r»d UKMy Oolo Brad 

32K EPAQW^HAM Mochila 

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1 B CMnntX PlraW I.C UaOjife 

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1 6K Ss*l "." RAW MJdul* 4T4>ii 

33K Kal < PAM 4J0ni 

3JK Siatc RAW MOni 

Ci^EiMMWr 

MjHflt* P"094JjmnijB*t T«n»jr 

fi Chanel Dviprta s,,,*) tO lAM 

lnr*lhQ«n|: Tip« Cffil'Wf 

JJS/32 l.-O Maa^le 

CentKt Oswtr Motiwt* 



LIST 

Pfl-CE 
t4B^0O 

I 39iOO 
175 DO 

7500 
10OOO 
275 00 
MS DO 

3900 
JlHQO 

4900 
230 DO 
35000 
«5Q0 
JJ400 
39500 
£» M 
99SOO 

MOO 
335 M 
3»00 
550 OO 
37SOO 
35000 






AP PL E/E X I D V / E XP A N D O 

THS SO 16K-UPGRADE KIT 



554,95 TRS-aO/APPLE 554.95 

MEMORY EXPANSION KITS, 

41i6'5, >6K(20G/250 ns,) 

Spctfpr*S4 H »5 

w/Enslruclinns & jumpers 

Call For Volume Pricing 

* Special: TRS80 Schematic S 495 

+ ExpanjHDJi Interface Schematic ..£ 4.95 

* Expansion I iierface Connector . . . 7.9fi 



IUpAUIAIaMIIMImorykits 

+ Baflh Selectable * Uses 41 IS 20D na. 

* Write Protect .«-* Power SVDC. ±16VDC 

* pnontom «gJS» * Up to 4 MHr 
BtpandoS4 Kit (41 161 Assem.S Tested Add S50. 

16K S2S9.00 4BK S435.00 

32 K $349.00 S4K S505.00 



HAZELTINE TERMINALS 

SALE 3749.00 

IAW 1400 SH9E0 UjWISffi] ti»5M 
Mcttt 1410 U»rx UxWISID 112450a 
UfllX i»D HaUl£» SUHOO 



5T? 



prom' 



Eraser 

Modal UVs-1 1 E £80.95 

Holds 4 E prom's al 3 lime 
Backed by 45 years 
experience. 

Mod.IS-32T_S2C5.rjO 
ProTesstonal Industrial Model 




^sSS!So 



EM AKO-SO- , R*S S77700 
UNBELiEVAELSII 
! f5C>pi HMcni -Vntal 
Femwl Untt - Wl CIwb- 
1tm - Uppo i.' Lmwr Cih - 
45" ro 9,5' AdjwtiUt 
■ BO col/40 C<H dOuW# 
wrflh - Fyll Wchal. ASCII 



EMAKCK22 $799.00 

Pn'ntt 1 1 32 cot'imfl. AvriiLabto with paralM or unar 
ouloul tt »m« once. 

MIKA20 $1290.00 

9x7, 125 cps 136 cJiarictcn/ihfie 
Fu« 15-" wWlh. Smfjor For btn|n«t (ppliC*1ions 
ragpjfNjg i*rg> \BM itxmti papar. 




BASE II PRINTER 

H Cai-jiM !Tip*rl Pnn 
■ flO LimM F»i UcpjU 
« 115/2-30 VAC. M 

attOHt 

* ri. So. w, l k 

i 17 Chv/Lnv 

■ it-Tal &Mb=h "^^"T^l^^^^ REO t*43 DO 

ACP PRICE $550,00 

OptrBn 'hT Twnwul ScrMn Bupltx ri 9K5 Crw ) . . ISOoa 

Cplron "S" Mflh Sptwf PlDOf AOrfllKV JL Gr.lrfiCI SO 00 

Optrai IT Tradnr FhcI BOCO 




» CPU BOARD 



Z-80/2-B0A/aOQ0 

* On board 2703 * 2 rofl included {450ns] 

* Power on jump # completely socketed 

* Z-80 Assembled and Tested ..... $1 85.00 

* Z-80Kil $129.95 

* Z-B0 Bare PC Boafd S 34.95 

* For 4 MHz Speed Add si 5.00 

HOBOAKil $ 99.95 

eoaoA Assemoiea si 49.95 



S-1 00 MOTHERBOARD SPECIAL 

6 slot expandable w/9 conn. 

reg$69 9S NOW 552.95 



SIEMEN'S FLOPPY 

■■■ jpictf buy ■*"** *j«eV tun 
* ft" r>tv*%<fh DCuO'P-O'Miiirt 



SALE 

SIEMENS 
£429.00 

SHUGART 

aoiR 

£475.00 



ACOUSTIC MODEM 

NOVATION CAT" 

0-300 Baud 

Bell 103 

Answer. Originals 5179-95 




DATA BOOKS * COMPUTER BOOKS 



?M0lCltfk«' 

MK -tl DM 
NfiCt.»w 



an mi»iHcs*oMirxHJ tso 

2 91 '-.:*' V-2^ a: wjrjji 4H 

ASS AMD tDKM Manual 5« 



.3431 

3» 51 UOSiVSJ OaU 495 

7» Ha-r* Anai^o 0*\kx<+ A 35 
LAW UC9UU(Mi 7» *1 L-*.ir Cfl«ral lOfM -3.M 



ZBO Prcgfimmmg 

V* M 5cr»* Ami Mcwouwh *'B««i 

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lSil : "■.. 
^0 F73 
*30 TJB 

■ 50 



§*^nr4i>'] ^Vui'f iSjdt 
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HVrwCvnptjlBTiVtf IHtVltMl 



»95 

. IK 
■0*5 



FIRST TO OFFER PRIME PRODUCTS TO THE HOBBYIST AT FAJR PRICES! 
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1980 CATALOG NOW AVAILABLE. 

Sand $2.00 for your copy of tho mott camp lata catalog of computer product*. 
A must for tha sarlous computer ut4r+ 



Ml C ROPROC ESSORS 



ztoot let-ttoiMb 


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ADVANCED SUPPORT 

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951 ^ Arm Prtx»MOr I7S-00 



I-BO SUPPORT CHIPS 



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JMUVDMA AOWHi 

;«>5l0fl 75WHi 

iBOA-StCW 40WH3 

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IflO-SBV? 40MK." 



75 
t2 95 
8,75 
:.'M 
2U95 
XB5 
35K 
39*9 
. 35S5 
. »4D 
3595 
3t**a 



aoao/aoes support 



■ 155-51 44 WJ 
>U755 l>0 wiiTi Einyn 
8207 Dyr> Ham Ctx*. . 
4.-05JT AS 1 S DKCd* 

JIUlMI'o 

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4JJ5 $>» CwlroT 
V»Svt Cvl 

5,351 Pr« I/O . 
4J!5Smnimtw 
BJSS ftgg t/O 
t2Sr Prog OMA 



24 94 
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3494 
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524 
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973 

2.95 
550 
550 

995 

1595 
550 
1595 



STATIC RAMS 




■ H 


25. M 


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1VU5J450* 


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1 75 


99 


nUHHH 


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1 53 


1 13 


2ttl 


3 Tj 


345 


353 


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2.15 


2 61 


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270 


255 


71 1 JL-J&Snr, |4y>JS| 


UN 


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550 


31 letirMm, 140*51 


UK 


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4,75 


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750 


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4.75 


EUU47O0A 


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795 


EMMHOa 


7« 


7 25 


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1150 


995 


5101 OC 


7« 


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UIDI14W41 


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10 J5 


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10 73 


116) 


19! 


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991 


■ 35 


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, r ar 


795 


723 


B418 IK ■ 1 OflCft 






7*4 


.■jH.-iSIf- I b-rfiam 






396 


i*'47'LcwPi»ai4<SfJi!<: 19 94 lB9i 


■■■■-■.; 




DYNAMIC RAMS 


















54 95 


4111 n 


<<:■ p.t 
























4DH4K 


■ ■ ntf Pm) 








2l04 4Kti|i4P<n| 






4T3 


4077 4Kcl H* Fv> 






4 95 


52S? 1 B-l 0"*l\ 


1103 


1 95 
4 95 


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EtiOl 


7 95 


5290 17 4', S 175 .00 


U04 
4S02 


4 95 
1 5A 






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-nP-r S*. iO ;4Pir» ST 50 


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51075 



FLOPPY DISK I/O 

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TV CHIPS/SOUND 

AV34400- ! 4 Oamtc KM 4.« 

ii.V3ft51 fi Cot5f Cwrtflu J 93 

AY34G03-I flMei:t&HM 8 91 

AT.3B604-I WlHiitfiiit CALL 

ATSBfiOtH Wip»3<44 Qi™ 950 

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AY»91QSaijnJankvxk>r i? 95 

5^144^^71 Sound Grw*or 3 95 

WinilM I Ttf&f** G*f 9»5 

IbHASaiinnrEMr . 345 

LMlBMAF.MoA^j'o' 3S3 

i."u i .• ■ od 'JSC Co»or TV S93 

MUSH&* CixkGvi 3:5 

Rr UcO^alcv *:*mJo .114 

Win MRhWcr M 95 

WAVEFORM GEN. 

BSifl *ifcxi!on 0*n 393 

m .: 2.n?AV. :::■ 395 

LK45S5VCO 1.93 

XFiriOS FuyKb«n G*n»rjl>i 575 

SHIFT REGISTERS 



LED READOUTS 



35104 t>«l 1D0 19! 

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33410-.JI.M 49! 

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CTS DtPSW.TCHES 

CTS2M-3 1 73 CT43C4V7 I Ii 

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C74304-5 174 CSS2D5-9 191 

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COMNECTORS I00L0) 



5300 SUPPORT CHIPS 

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1432 

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PROMS 

S70aj45QrTE 


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11 95 
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CHARACTER ( 

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CIRCLE 9 ON FREE INFORMATION CARD 



143 



LONG PLAY 
10 HOUR TAPE 
RECORDER 



Top quality AC-DC cassette 
recorder, modified to provide 
5 continuous hours of re- 
cording and playback of true 
fidelity, distortion-free sound 
on each side of cassette fur 
3 total of 10 hours. Unit has 
many special built-in fea- 
tures. TDK D-G1S0 cassette 
supplied. 




ohly $125,00 



PHONE RECORDING ADAPTER 



Record Incoming and outgoing 
calls automatically with this all 
solid state unit connected to 
your telephone jack and tape 
recorder. Starts recording when 
phone is lifted. Stops when you 
rung up, making a permanent 
record. Easily Installed. No 
monthly charges. „. _ nvt 
FCC APPROVED J24.50 




VQX VOICE ACTIVATED 
CONTROL SWITCH 



Solid state. Self contained. Excel- 
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trol recorder. Uses recorder mike or 
remote mike. 

2W x 1% x «" $24.95* 



% 



Phone call Adapter S24.50*. VOX $24.95*, ('plus 
$1.00 ea. shipping 8 handling), 10 hr. Recorder 
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CIRCLE 34 ON FREE INFORMATION CARD 




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CIRCLE 32 ON FREE INFORMATION CARD 



*••••■*•••••• 

TRS-80 
OWNERS 

*** + **************** + ■* 

The "Original" TRS-80 
JOURNAL is now entering it's 
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MO TODAY to: 80-U.S. 
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CIRCLE 17 ON FREE INFORMATION CARD 



m 
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Xerox copies ot individual articles can also be 

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Please write companies 

for complete information 



144 



CIRCLE 14 ON FREE INFORMATION CARD 




vc/t. 



ELECTRONICS 



INTEGRATED CIRCUITS 



P.O. Box 4430E 
Santa Clara, CA 95054 

Will calls: 2322 Walsh Ave. 
(408) 988-1640 
Same day shipment. First line parts only Factory tested 
Guaranteed money Men Quality tc s and other compo- 
nents at factory pnees 




PROM Eraser 

assembled 25 PROM capacity $37.50 
iwitii timer 369.501. 6 PROM capacity 0SHA/ 
UL version JSS.50 (with timer $94.50) 

ZS0 Microcomputer 

16 Pit I/O, 2 MHt clock. 2K RAM. ROM Bread- 
board space Excellent lor control. Bare Board 
$28.50. Full Kit 199,00. Monitor $20.00. Power 
Supply Kit $35.00. Tiny Bali c $30.00 

S-100 Computer Boards 

SK Static Godbout Econo HA Kit 145.00 
I5K Sialic Godboul Econo XIV Kit 285.00 
24K Static Godbout Econo VIIA-24 Kit 435.00 
32 K Static Godboul Econo X-32 Kit 575.00 
16K Dynamic RAM Kit 199.00 

32K Dynamic RAM Kit 310.00 

64K Dynamic RAM Kit 470.00 

Video Interlace Kit 1135 DO 

60 IC Update Master Manual $55.00 

Camp IC data selector. 2700 pg. master reference 
guide. Over 51 .000 cross references. Free update 

service through 1990. Domestic postage $3.50. 

Modem Kit $50.00 

Slate of the art. orig,, answer. No toning neces- 
sary. 103 compitibta 300 baud. Inexpensive 
acoustic coupler plans included. 
LFtC 7000 t Printer $389.00 
40 so column dot matrix impact, std. paper. 
Interlace all personal computers. 

64 40 32 20 version $405.00. Optional cables 
available. 

LRC 7000 printer interlace easts fnr Super EH 
with software $25.00 




NiCad Battery Fixer/Charger Kit 

Opens shorted cells that won't hold a charge 
and then charges them up. all in one kit w/tull 
pans and Instructions $7.25 

Rockwell AIM 65 Computer 

6502 based single board with lull ASCII keyboard 

and 20 column thermal pnnter 20 char, alphanu- 
meric display, ROM monitor, fully expandable. 
$375.00. 4K version $450.00. 4K Assembler 
$85,00. SK Basic Interpreter 5100,00 

Special small power supply for AIM65 assem in 
frame $54.00. Complete AIM65 in thin bnefcase 
with power supply $499.00. Molded plastic 
enclosure to (it botti AIM65 and power supply 
$47.50. Special Package Pnce 4K AIM, SK Basic, 
power supply, cabinet $599.00 

AIM65 KIM VIM Super tit 44 pin expansion 
board, 3 female and 1 male bus. Board plus 3 
connectors $22.95. 

60 Hz Crystal Time Base Kit $4.40 

Converts digital clocks Irom AC line frequency - 
to crystal time base. Outstanding accuracy. 

Video Modulator Kit $8.95 

Convert TV sel into a high quality monitor w/o 
affecting usage Comp kit w/fuH instiuc 

Multi-volt Computer Power Supply 
Bv 5 amp. ^18v Samp, 5v 1.5 amp. -5v 
.5 amp. 12v Samp, - 12v option . ::5v, i12v 
are regulated. Basic Kit $29.95. Kit with chassis 
and all hardware $43.95. Add $4 00 shipping. Kit 
of hardware $14.00, Woodgrain case $10.00. 
SI. 50 shipping. 



RCA Costnac 1802 Super Elf Computer $106,95 



Compare features before you decide to buy any 
other computer There is no other computer on 
the market today that has all the desirable bene- 
fits 61 the Super EH for so little money The Super 
Elf is a small single board computer thai does 
many big things It is an excellent computer for 
training and tor learning programming with its 
machine language and yet it is easily expanded 
'with additional memory, Fuil Basic. ASCII 
Keyboards, video character generation, tie. 
Before you buy another smalt compter, see d it 
includes the lollowing features: RDM monitor,' 
Stale and Mode displays: Single step: Optional 
address displays: Power Supply: Audio Amplifier 
and Speaker: Fully socketed for all JC's: Peal cost 
of in warranty repairs, Full documentation. 
The Super EH includes a BOM monitor lor pro- 
gram loading, editing and execution with SINGLE 
STEP for program debugging which is not in- 
cluded in others at the same price. Wrth SINGLE 
STEP you tan seethe microprocessor chip opera- 
ting with the unique Quest address and data bus 
displays before, during and alter executing in- 
structions. Also. CPU mode and instruction cycle 
are decoded and displayed on 8 LEO indicators. 
An RCA 1361 video graphics chip allows you lo 
connect to your own TV with an inexpensive video 
modulator to do graphics and games There is a 
speaker system included for writing your own 
music or using many music programs already 
written. The speaker amplifier may also he used 
to drive relays tor control purposes. 



plus load, reset, run, wilt. Input, memory pra- 
ted , monitor select and tingle tlep. Large, an 
board displays provide output and optional high 
and low address. There is a 44 pin standard 
connector slot lor PC cards and a 50 pin con nee-* 
tor slot lor Ihe Quest Super Expansion Board. 
Power supply and sockets for all IC's are in- 
cluded in thepriceplusadetarled 127 pg. instruc- 
tion manual which now includes over 40 pgs. of 
software info, including a series of lessons to 
help get you started and a music program and 
graphics target game. Many schools and univer- 
sities are using the Super Ell as a course of study. 
OEM's use it for training and R&D 
Remember, olber computers only offer Super Ell 
(eatu res at add itional co st o r hDE at al I . Cumpa re 
before you buy. Super Elf Kll $106.95, High 
address option $8.95, Low address option 
$9.95. Custom Cabinet with drilled and labelled 
plexiglass Ironl panel $24.95. All metal Expan- 
sion Cabinet, painted and silk screened, with 
room for 5 S-100 boards and power supply 
$57.00. NICad Battery Memory Saver Kit SS.95. 
All kits and options also completely assembled 
and tested. 

Quetldala. a software publication tor 1802 com- 
puter users is available by subscription tor 
$12.00 per 12 issues Single issues SI. 50. Is- 
sues 1-12 bound $16.50. 
Tiny Basic Cassette $10.00. on ROM $38.00, 
original Elf kit board $14.95. 1802 software; 
Moews Video Graphics $3.50. Games and Music 
$3.00, Chip 8 Interpreter $5.50. 



A 24 key HEX keyboard includes 16 HEX keys 

Super Expansion Board with Cassette Interface $89,95 



This is truly an astounding value! This board has 
been designed 10 allow you to decide how you 
want it optioned The Super Expansion Board 
comes with 4K of Eow power HAM fully address- 
able anywhere in 64K with built-in memory pro- 
tect and a cassette Interface. Provisions have 
been made for all other options on She same 
board and it fits neatly into the hardwood cabinet 
alongside the Super Elf The board includes slots 
lor up to 6K ol EPROM (2708. 2758. 2716 orTI 
2716) and is tully socketed. EPROM can be used 
foY the monitor and Tiny Baste or oth er purposes . 
A IK Super ROM Monlior $19.95 is available as 
an on board option in 2708 EPROM which has 
btin preprogrammed with a program loader/ 
editor and error checking molti file cassette 
read/write software, (relocatable cassette iilc.i 
another exclusive from Quest, It includes register 
save and readoul. block move capability and 
video graphics driver with blinking cursor. Break 



points can be used with the register save feature 
to isolate program bugs quickly, then follow with 
single step. If you have Ihe Super Expansion 
Board and Super Monitor Ihe monitor is up and 
running at the push of a button. 
Other on hoard options Include Para lift Input 
and Outpul Porta with lull handshake. They 
allow easy connection of an ASCII keyboard to the 
input port. RS 232 and 20 ma Current Loop for 
teletype or other device are on board and if you 
need more memory Ibere are two S-100 slots lor 
static RAM or video boards. Also a 1K Super 
Monilo r version 2 with vid eo d river fo r fu It cap a - 
bility display with Tiny Basic and a video Interlace 
board Parallel I. ID Ports $9.65, BS 232 S4.50, 
TTTf 20 mi l/F $1.95. S-100 $4,50. A 50 pin 
connector set with ribbon cable is available at 
$15.25 for easy connection between the Super 
Elf and Ihe Super Expansion Board. 
Power Supply Kit for the complete system (see 



Mulb-volt Power Supply). 

Announcing Quest Super Basic— SECOND GENERATION 

A new enhanced version of Super Basic now Enhancements Include increased speed, built- 



avallable. Quest was the first company worldwide 
to ship a full size Basic for 1802 Systems. A 
complete function Super Basic by Ron Cenker 

including floating point capability with scientific 
notation 'number range - I7E"). 32 bl t integer 
±5 billion, mutti dim arrays, string arrays, string 
manipulation, cassette Ij'O, save and load, basic, 
data and machine language programs: and over 
75 statements, functions and operations. 



In provisions (or Stringy Floppy, Floppy Disc. 
Printer Driver. I/O, user definable command 
library and statement renumbering. 
Easily adaptable lo mosf 16Q2 systems:. Re- 
quires 16* RAM minimum for Basic and user 
programs. Source listing lor both Serial and 
Parallel I/O included. 
Super Sasic on Cassette $40.00. 



Gremlin Color Video Kit $59.95 

32 x 16 alpha'num erics and graphics: up to B 
colors with 6847 chip: 1K RAM at EOOO, Plugs 
into Super Elf 44 pin bus. No high res. graphics. 
On board RF Modulator Kit $4.95 



1802 16K Dynamic HAM Kit $149.00 

Expandable to 32K Hidden refresh w/docks up to 4 
MHz wmo wait slates. Addl. I8K RAM $63.00 
Super Elf 44 pm expansion board. 3 female and 1 
male bus Board plus 3 connectors $22.95 
Tiny Basic Extended on Cassette $15.00 

(added commands Include Slringy. Array, Cas- 
sette M) etc.) 

$-100 4-Slol Expansion $ 9.95 

Super Monitor VI. I Source Listing $15.00 



Ell II Adapter Kit S24.95 

Plugs into Ell II providing Super Elf 44 and 50 pin 
plus S-100 bus expansion. (With Super Ex- 
pansion) High and low address displays, state 
and mode LEO's optional S1B.00, 



Super Color S-100 Video Kit $129.95 

Expandable to 256 x 192 high resolution color 
graphics 6347 with all display modes computer 
controlled. Memory mapped. 1K RAM expanda- 
bletoGK S-1OObus1B02,8OBO 8085. 280 etc. 
Editor Assembler $25.00 

(Requires minimum ol 4K for E A plus user 
source) 

1B02 Tiny Basic Source listing $19.00 

Super Monitor V2.02.1 Source Listing $20.00 



TERMS: $5 00 mm order U.S. Funds. Cattl residents add 6% tax. 

$10 00 mm order BankAniericard and Master Charge and COO. $1.00 insurance optional 
Shipping charges will be added tin charge cards. 



FREE: Send for your copy ol our NEW 1 980 
QUEST CATALOG. Include 48c stamp. 



O 
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CIRCLE 78 ON FREE INFORMATION CARD 



145 



IS YOUR 



Electronics 

LIBRARY 
COMPLETE? 

Back issues are available for most 
months of the last (3) years @ $3.00 
each, postpaid. Please send your 
check or money order to: 

RADIO-ELECTRONICS® 

BACK ISSUE DEPARTMENT 
200 Park Avenue, South 
New York, NY 10003 

Name 



(please print) 



Address 

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State . 



(please print) 



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Issue(s) requested: (if available) 

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ELECTRONIC 
DESIGN LAB CA-16 




Components not included 

• Variable function generator 

I HZ to 1O0 KHZ TTl, CMOS logic levels 

• Six regulated supply voltages, all short 
circuit proof, including 5 volt I amp 

• Four logic indicators and dcbonncc switches 

• Two CMOS to TTL convenors 

• Two large breadboards, all point to point 
connections— no soldering 

Everything is at the users finger tips. Our 
Design Lab will soon pay for itself in time 
and component savings. An excellent aid 
for engineers, technicians, students, and 
hobbyists. $99.95. 
Free brochure 
CASCADE LABS 

4 156 South Alder Avenue 

Freeland, Washington 98249 (206) 221-7483 



CIRCLE 69 ON FREE INFORMATION CARD 



THESE PRICES! 
ARE NOT 1 
MISPRINTS!! 

Limited quantities — First come, first served. 
Sorry, at these low prices we cannot include spec 
sheets or accept COD/telephone orders. tC 

numbers must include the special -S suffix or you 
will be charged our regular prices. Parts may be 
house numbered ar have dual markings. 

SOLDERTA1L SOCKETS 



Spin: 100/55,95 

14. 16, 6 IB pin; 50JS4.95 

20 pin: 40/8 4.95 



J4. Z8 pin: 30/S4.95 
40 pin: 20/34.95 



16K DYNAMIC RAM SPECIAL: 8/$39 

THE PRICE IS RIGHT for expanding memory ml 
I TRS-80* -I and -II, oi well as many oilier machines. T 
Low power, high speed (4 MHz). Add 43 for 2 dlpl 
| shunls plus TRS-B0* conversion Instructions, 

■ I K!- £<'■ , ■' trademark el l>t« Tandy Can .„j' -.■, 

ItfJ 401 2-5 

- 40ZQ-S 

■ _. 4023S 

IE, 4044-S 

j(U 4046.S 
407 1 -S 
4093-5 
4507-S 
451 OS 

[OTHER SEMICONDUCTOI 

Qen purp signal diodes 50/! 2 
QT530S NPN dorlinglon 100/48.95 
NPN sim JN3904 100/*7,95 
PHP sim 2N2906 100W8.95 

4rt;e-s opio-i»i. 5/«2 

SN76477-S sound [C 1/42.50 
MAI003-S 12V DC clock module 14.95 

SEND FOR FREE FLYER ift^JSg 

■ TERMS: Cal fa* add la*. Altow 59i tar ahippmp- «■;<:» j^lundtd 

■ Order* under Hi atfd *l handhnrj We accept VIBA'tftaitftr 
^| card* order* <t-23 mln), I'leaifi include iirc-ci «Jd»«5 for tlP£ | 

f. Ptkpj gutxt t.hrrjuLjti ro^c" month of rnaflaftne 



12/92 


* ill 






4/42 


201 HS 


10/42 


12/42 


308H-S 


6/42 


4/42 


<l n 1 ; 


703HS 


6/42 


2/42 


UlS,** 


723DS 


6/42 


12/42 


siiS 


741M-S 


15/42 


4/42 


I458M-S 


10/42 


4/42 


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4558M-S 


12/42 


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4 I95TK-5 


2/42 




GODBOUT i 
BfrJcj. 725, Oakland Airport, 

CIRCLE 47 ON FREE INFORMATION CARD 



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BILLET ELECTB-SIICS 



NPN HIGH VOLTAGE 1.59 

VCEO = 450 VOC IC = 3A (5A Peak) 
FOR TV HORIZONTAL SECTIONS; HIGH 
VOLTAGE REGULATORS 
REPLACES: 2N5G76, 2N5077. 2N5S3B. 2N5695, 
BDY&4. BU126. 2SC2121, 2N5S40. 2SC1046. 
!N5466. TIP556 AND MANY OTHERS. 



[HOUSE « 



LM3046 (CA3046) Transistor Array 75 

RCA 40430 400V 6A TRIAC TO-86 .75 

C A 308$ RCA Transistor Array 80 

LM567 Tone Decoder B9 

004046 PLL CMOS .99 

LM33Q2 Ouad Comparator 89 

2SC1849 High Freq NPN TO-92 6/1.00 

MPS A20 NPN GEN PUR 8/1,00 

Sound Effects Kit $18.50 

ThaSE-Lrl i» a COrrlptoUj kit (hat 
ConUTU. ill Mia paria La build a 
pt og- a mm a biff sound aMttli 
Qoncalci? Dciijjfi-c-J abound 
MiB naw T*»« rn ar.ru man ft 
ENJM77 5-su.rid Chip, the 
"v-»- A r ,,m > A hoard pidvtdffS banka fll MINI 

*w* I.' ,Jfc ii*l Jt-T- "s DIP ifjtchaa and pot*. [& 

|'"* l iC?i J P*fjrjr fl m Ififl vanflLt* Cfim. 

I"*** ^ ^_y tHnaEionn LThJic 3LF Oscillator, 

LVCD. Hone. On* Shoi, and 
— — - Envelope Controls AQuidOp 

Amp IC ia uaad lp implamam 
an AdjuacaHa Pu'w Ganera- 
icw. Ltrti CcmiMjatei Ana 

^,JJl> MullipIC* OSCiJIfllor ro- won 

»^^H : I ■*»* mOf morr? vprsaEilrly ■'■he 3 ■ it 6 

^HB 14 *^*>^h w -' Us:-va FBBtunm a. pffflalypi 

BU^tlAVv 1 ! arffj Do tMUj* lor uicr acoco 

citii.ii,' Eiiiiy prpgrammrthtf 

IO Uupl I...TEC- Eiplenjoni. 

Pnaior Sum. Slvim Traim. or 
■lnvcn-1 rin inrmiie numbar o' 
Dthar liundi TJie untl iu- a 
mulliple m I applnrallona Thi 
iiw pn;# meJudH atl patn 
■unmNy manuai. pri^rammmg charij a-n nria i c j 7&I77 chup «o«c>- 
riCBUfifil II Ivnl pn a 9V tialieiy (no( induOM], On board 10QMW a.mp 
win jri-, n a small !puk«r dlrfrcMy. ar thn un>1 cm f-v amnncwt 10 your 
iicica v-un ihcrgdiblfl 'rsjiis' (Speaker noE m - Kr dr-i . 

• 7G4T7 CHIP IS INCLUDED. EXTRA CHIPS *a,iS EACH 



AY3-991Q PROGRAMMABLE SOUND GENERATOR 
The AY3-B910 Is a 40 pin LSI chip with three oscillators. 
: 1 1 ree am pll Lude co n trols , program ma ble -^0 i s gs n a m : 1 
Ihree mixers, an envelope generator, and three D/A 
converters that are controlled by 6 BIT WORDS, No 
external pots or caps required. This chip hooked to an 8 
bit m ic ro processor ch i p or Buss (S0BO. 2&Q , 68D0 etc.) can 
be software controlled to produce almost any sound, tt 
will play three note chords, make bangs, whistles, sirens, 
gunshots, explosions, bice's whines, or grunts. In 
addition, it has provisions to control Us own memory 
chips with two 10 ports. The chip requires +5V @ 75ma 
and a standard TTL clock oscillator. A truly incredible 
circuit 

$14.95 W/Basic Spec Sheet (4 pages) 
60 page manual with 5-iQQ Interface instructions and 
several programming examples, $3.00 extra. 



V2W RESISTOR ASSORTMENT 

A good mi* of 5S and 10**va,i JUS in both full l«ad and PC lead devices All 
new. i«r si quality 

.{AaE-l 1 200 piotos..'2,M 



7 WATT AUDfO AMP KIT 

SMALL. SINGLE HYBRID IC AND COMPONENTS RT ON A 7~ x i" PC 
SOAftDHNCLUOEDJ.FlUNSON 12VDG GREAT FCH ANY PROJECT THAT 
NEEDS AN INEXPENSIVE AMP LESS THAN 1% THD r$ 5 WATTS 
MMjPATMkl YJI7H SE-Qi SOUNO^iT t5.« 



ULTRASONIC RELAY KIT 
INVISIBLE BEAM WORKS LIKE A PHOTO ELECTRIC 
EYE. USE UP TO 25 FT. APART. COMPLETE KIT. ALL 
PARTS & PC BOARDS. $21.50 



THE PERFECT TRANSFORMER 
117VAC primary. 12VAC secondary @200ma 
Great for all you CMOS, or low power TTL 
projects. PC board mount. 99c ea. 3/52-50 
Size: 1.5" W x 1.25" D x 1.25 "H 



XAN SUPER DIGITS 



.99 



RED 

7 SEGMENT 



.6" JUMBO LED 

5920 COMMON CATHODE 
&&40 COMMON AnCDE 

NOW A SUPER READOUT AT A SUPER BUY! Thaw Are l*clory freah 
prima LEO readout*,, n tjl a«conrjiB or rejects la sold by o\ hers Compare our 
price And send for youra lc-day. tml hurry, (he supply ii firm ted' 
SPECIFY; COMMON ANODE OR COMMON CATHODE 



0m\\®nd IK 7SQ4i 

**^ MUSIC FOR YOUR EARS 

Bullet's Elociranic Music Mrker r " Kit hma a single 2& Pin 
Microprocessor Chip wllh ROM that has been 
programmed lo play the Urst 6 lo 10 notes oi lhe2S popular 
tune* listed below. Each tune can easily be addressed 
individually or played sequencially at the push ol a button. 
The 3 chime sequences are activated at any lime by 
separate switch closures so when used as a doorbell, on a 
door can pJay songs while two olhers will play different 
chimes The unit has a S watl audio Amp and will run on 
ellheriaVAC or 1ZVDC. Optional 117V AC Sransformer is 
available Construction is very simple, works with anyS or 
16 ohm speaker, or horn speaker. <Nol Included.) Tunes 
can be remotely programmed using a single rotary switch, 
(not included), if desired 

Complete KM S16.95 Transformer SI .35 

{For operailon on 1 17VAC) 

Tun**: T*rr«rfor ' WltliinTfll- HlJmulahChWlu' SUrSpjingUdBannTr 
'Yankn DrweJU ' Amtrlea. Amprlca " Dntichlintf L aU " W'tddHtg M jrrch 
' BMthCrvrn'tSlhindS-ln • Hdl'iPflt ' La VHftEn flDif Sl*r W*n TJ«ffl» 
1 Clnmemin.* " Auejui||(h * Jlngla Balk ■ Gad £>*( Th< ClUu*n ' Colonel 
(tooay ■ Mar»lluiii> 1 OS0I4UI4 ■ SanlaLuda *Trw End' Qiu# Oanub*' 
Srahmi Lultptjy ' Wtubnrrklattr Chlrnv " Simpl* Chlm* ■ D*tCind.lng 
Oetiva Chhri*. 

PARTS 

TL4SD Bar/Graph Driver .....,.....,„,,.,,,,... 2.SQ 

VflGS SV 1A FtogulalOt .SB 

78M05 »A TO-6 Rag SV (Hse. #| 60 

LM3911 Temp. Transducar 1.1C 

555 Timer IC 4fl 

TI3 Voilage Flag. 14 Pin Dip 50 

TSiz lAiavReg .99 

2N6028 PUT W/SpBM SO \ 

IL-1 Oplo Isolator W/Specs .60 | 

» NO C O D.'s 

* SEND CHECK MO OR CHARGE CARD NO 

* PHONE ORDERS ACCEPTED ON 

VISA AND MASTERCHARGE ONLY 

(214) 278-3553 

* ADD 5% FOR SHIPPING 

* TX. RES ADD 5% STATE SALES TAX 

* FOREIGN ORDERS ADD 10% (EXCEPT CANADA) 

(20% AIRMAIL) US FUNDS ONLY 



146 






DIGITAL MULTIMETERS 



Sinclair 
PDM35 

Reg S6995 
S 49 95 



LX303 
*69 50 



this ad] 



FREE 8 



pTto^Uv^^*^ 



Logic Probe 

■ Com o,i in orcijiT poiveJtO ■ 
Dtfecs puises as shor: as 50 

m «c>dtlttlhtlcmcs 

corneal iOili1> 



Mflte; LP ■■ 



Kutnynmu, IHCwim 



Function Generator 
s 157 95 



Model 2DD1 
Rf.j 5195 35 
■ S'Oc squarr 
JiLangic- and 
jepmIbTTL 
sauar* wave 
oul put 



100 MHz 8-D>git Counter 

■ I'D Hi in 100 WHi range • LED display ! 

■ Fufly automatic a™ S-CVTSO 
ModelMAXlOO S'SODO 1^/ 



Preassemhled Proto 
t£^*V Boards 

Model \-*»-% tjAQ<; 

Fully as&emtjred breadboard 
contains lour QT-59S sockets 
seven OT-59B bus slops and Tour 
5-rtav binding posts 



Proto Board with 
Built-in Power^^ 
Supplies /v^^i 

■ Regulated C.'tfiSS/ 

■ Snort-prodl KL^ "f/ 

Fttg sis<9s ^%yy^ 

*129 9S Mode! PB-203A 



3Vz-Digit Q.1% Digital 
Capacitance Meter 

■ 3 ranges Ijom 1999 pF to 199 9iiF 

* 1% oi reading accuracy ■ Auto 
over And under range indication 



Model 3001 
Res 5190 00 

>*170 



Portable Digital 
Capacitance Meter 

■ Vcassjirs apaeilan-ee Irom 
IpFio 1 Farad ■ Resolves it? 
Q TpF » iQ ranges lot 
accuracy and rewluiinn ■ 4 
diQii easy-to-read LED display 

■ D 5", accuracy 



] Beckman 
TECH310 « 

■ 22 Ml J mpul 
resistance" 10 Amp 
AC OC ■ 1 500V Overload 

■ 6KV Transient 
ProHrClaon ■ 2 yeap 
Sscccry htf 



*140. 



IT 1 

Simpson 461 

Complete ailh nickei- 
cadmium batteries AC 
cnaiger adapter sesl 

luds *1 49 95 



LEADER 



3Vz-Digtt OMM 

with LCD Readout 

■ -0 1'^ DC accuracy » 5" 
LCD display to' nigh 

T.-iKih-l ly • ID'li.A LUiienl. 

iange- lOQ^V IQOnA 01 
U resolu'i&n ■ Battery lite of 
over 100 hours ■ S^ielde0 10 
stay accuraie in RF (.elds ■ 
Low battery warning 1 



25 MHz 
Dual Trace 
Time Base, 



Dual Trace 5" 30 MHz 
Triggered Scope 



■ Rise time 11 7 nS or 
less ■ Built-in signal 
delay line ■ Fiai 
response mi- smootn 
ipiloll past JO MHi • 
5mV 'cm vertical sensitivity 
Prpoes irictuded 
Call lor Discount Prices 



Q 



;e -;«.",.' 



RF Wide Band Signal 
Generator Model lso-ib 

■ Solid stale FET oscillator circuitry ■ 
100 KHI to 100 MHi Irerj range ■ 300 
MHz on harmonics 

Transistorized 

Model LCR-740 S 



with Calibrated 
Variable Delay 

Model LBO-515A with probes 
■ 1 usee 10 5 sec Bttnt-ifi delay 



■ Hifjhty accurate 3 dirj.ii readout ■ 
Operates on one 9V ballery or y.-ifh AC 
adapter ■ Measures mdudaoce 
capaGtan.ee resistance and loss Factor 



20 

MHz Dual 

Trace Oscilloscope 

Model LBO-508A wrlh probes 

Call lor Discount Prices 



TECHNICIAN AIDS 

Welter'- Xceltte' 

Attache 
Style 

Model TC iOO SI 

W £V299 95 _ 

Service 
Master 

Model 99-SM 

„& *49 95 i 

EDSYN SOLDAPULLT* 
Desolderinfl Tool *16 95 

^^--—■7,^^=^ Model OS017 



Mods! 
7S00 



'^^ Cordless Soldering 
6© Iron *29 95 

WAHL 



Model 
5»30 



Thwnai-Spat $29 95 

Circuit Tester 

Finds lauity comoonents 
quickly and easily 



Welter-Controlled 

Output Soldering 
Station 
Econo-Lamp 

I balanced arms ■ 

control knous ■ Baked 

Finish ■ Colors. Red 
Yellow Blue Black, Oyster 
mile ■ ul tor WW 
Model XL-3MA S"| 095 



Model WTCPN 
Rib s^so 

5549S 

Magnifier Lamp 

nd and pO'ishEd 

» 4 g50 



CAR STEREO PRODUCTS 

In- Dash Car Stereos 

ir~~~" "^X 3-Trsck Tape Player with 

1 x w*^SiP- AMFM. MPX Radio JM S0 

■■■^^m-v- Muieic-777 ^oZ 3 " 

Auto Reverse Cass elle Tape 

1 Player with AH FM MPX Radio 

Model CAS 999 s 79 95 

Cassette Tapo Player with 
AM FH MPX Radio 

Model CAS -a la 



s 57 50 



RWVIWI HICKOK 



30 MHz 
Portable 
Frequency 
Counter 

Reg 3130 00 

H 



Digital CB 
In-line Testerl 

■ Measures ail 4 
Irajismitte' outpuf i 
characlensEiics. ■ " 
Frequency ■ Power 

■ SWfl ■ Modulation 1 



Model 25& 



wev 



SPECIALS 

RCA-VIZ 

Super Chro-Bar 

Model WR-53SA 
Reg S!!9 9S 

sggss 



Stereo Power Booster 

Model pow-iO 

■ JOWslcreo 

■ ?DW per chinnet $Oyi 95 

■ Bass oodsi tt 



Chess Challenger 7 

■ 7 levels oi play t 
motel Bs;; 



Reg SriO DO 

S7995 



«!£?" F 



l\ 



"iK^ 1 ■ io«i«w 



^*19 9S 

' Model VM52Q 



■ 36 resistors 1 15 ! 
10 10 ME!)- 18 
capacjEPrs(lOOpMo 

Rej S49 95 H&. 

includes test leads 



TELEPHONE 
DEVICES 

MURAPHONE 
Cordless 
Telephone 
System 

, F. ^ fQ 



CODE-Jl-PHONI 

Telephone Answering 



Model WC412A 



BSRX-10 



.^ijfc 



CANON Calculator 
Portable Printer with 
Adding Machine Tape 

Model PI D-D 

*69 98 



6" x 9"j 
3-Way 
Speaker ' 

Model $1 A95 

BPIMD-69TF! ' ^63. 
■ 20 07 ceramic magnel 

Miniature High Fidelity 

3- Way Stereo Speakers 

MINI speakers 

KAXJ 

sound 

Model 

Mf-9 

*69 pf RBI Sr-19 35 

■ Die Cast Aluminum ■ LongTIirow 
Woolei - Sol! Dome Tweeter 

■ Emended Midtange Speaker 

■ eozoonOHn sow 8onms 



Portable Oscilloscopes (flfe 
15 MHz J™ 

Dual Trace | 

Triggered 

Miniscope 

•389" SS 

15 MHz Triggered Miniscope 

Model MS-15 Kit S3« 80 SOQQ95 

30 MHz Dual Trace 
Triggered Miniscope 

Model MS-Z30 Reg S599 IS '499^ 



Model MS-SIS 
*65 45 



fl emote Control for 
Lights & Appliances 



c3^ 



1MS 

■ - ",ii.ng 

Reo SJ99 M Model HOD 

*279 9S S 199 9S 

GTE Flip-Phonej" 

S 37 95 



Model lioo 
Cj.i Ccmioi 
Rig SJJS3= 

s 2 499s 



* Pc StindBf -d Sutler Ktl * Om [ 1 j Stwflirl, Comnjnfl fl*fi 537 95 

■ Tw m uikp Moautts ■ om Hi *op4jfl» iyQ50 

S PC UlEniDnic SEirler Kil ■ Qf* til □wiur? ItlrWrWt ; 

U CanwM • 0"»e rtanrf Hrtd Rcn^ti- uimr * Ttt SQQS5 



■ 



(■(Vr#|Tl Ajpirta Uni' 



$14,50 "-■"■ S36.00 

S14,SO Jl'J--.»i " , v'"^:'J'ernni; 

114 50 *Jft rtjrtu rwka n* 1 -.-.;- ^aa-aa 



'.' i. 



• Ct»«* . , onte add appropriate sates tax 
N.Y. S' a * e residents ac M t 



0)b4D-9518 



in N.Y. State 



O 
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147 



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148 



100 W CLASS A 
POWER AMP KIT 

Dynamic Bias Class "A" circuit design makes this 
unit unique in its class. Crystal clear, 100 watts 

power output will satisfy tile most picky tans. A per- 
fect combination with Ihe TA-1020 low T.I.M. ste- 
reo p re-amp, 
Specifications: 

• Output power: 100W RMS imp 8- ohm 

125W RMS into 4-oh,m 

■ Frequency response: 10Hz - 100 KHz 
. T.H.D.: less than O.0OB% 

• S/N ratio: better than 80dB 

• Input sensitivity: IV max. 

■ Power supply: ±40V (§> 5 amp 



mJt 



TA-1000K1T 
$61.95 

Power 
transformer 
$15.00 sach 



PROFESSIONAL 

10 OCTAVE STEREO 

GRAPHIC EQUALIZER!! 




Graphic equalizer have been used for years in sound 
studios and concert arenas but were too expensive 
to be considered for home use. -Now we offer you Hie 
facility at an affordable price. This unit can extend 
your control of your Hi-Fi system by minimizing the 
non-linearities of the combined speaker/room sys- 
tem. Fantastic features as follows: 

• 10 double slide controls for two channels 

• Cut out rumble, surface noise and hiss 

• Minimizes speaker/room non-linearities 

• Frequency response from 30Hz to 16KHz 

• 10 tone controls plus defeat, monitor and tape 
selector. 

• Control range ± l2dB in 10 octaves OOHi, 60Hz. 
120Hz, 240Hz, 500Hz. 1Ktta. 2KHz, 4KHz, oKHz, 
16 KHz.) 

• Operating voltage 117V 50760Hz. 

FACTORY ASSEMBLED IN IT, NOT A KIT 
SPECIAL PRICE S117.00ea 



SUB MINI SIZE FET 
CONDENSER MICROPHONE 

1\ Specification: 

%\ Sensitivity: — 65dB ± 3db 

\V FEQ. Response: 50 Hz 8 KHz 

^^ ^^^ Output Impedance: 1K ohm max. 
^%i^^h Polar Pattern: Omni-directional 
WW Power Surjply: I 5V IDVD.C. 
^» Sound Pressure Level: Max. 120dB 
EM4RP $2.50 ea. or Z for S4.50 



NEW MARK III 

3 Steps 4 Colors 

LED VU 

Stereo level Indicator kit with arc-shape display 
panel!! I This Mark III LED level Indicator is a new 
design PC board with an arc-shape 4 colors LED dis- 
play (change color from red, yellow, green and the 
peak output indicated hy rose), The power range is 
very large, from -30d8 lo +5dfl. The Mark III in- 
dicator is applicable to 1 watt - 200 watts amplilier 
operating vollage is 3V - 9V DC at max 400 MA. The 
circuit uses 10 LEDs per channel. It is very easy to 
connect to the amplifier. Just hook up with Ihe 
speaker output! 

IN KIT FORM 518.50 



SOUND ACTIVATED 
DISCO LIGHT KIT 

Latest design electronic color light organ, with bolh 
sound and line input, the Ihree color tights [not in- 
cluded) will change colors wilh the rhythm of the 
music: controlled by 3 ranges, low, middle and high. 
Ideal for party, bar, or home entertainment. Max. con- 
trolled output • 000 wafts per color (3 colors). 
Kit includes aluminum cabinet, all electronic pari; 
P.C. board, and transformer. 

(Color Organ) 
$49.50 per kit 



TY-23 




MARK IV 15 STEPS 

LED POWER LEVEL 

INDICATOR KIT 

This new stereo level Indicator kit consists of 36 4- 
color LED (15 per channel) to indicate the sound 
level output o( your amplifier from — 36dB *» +3dB. 
Comes with a well-designed silk screen printed plas- 
tic panel and has a selector switch to allow floating 
or gradual output indicating. Power supply is 6 — 
t2V D.C. with TUG on board input sensitivity con- 
trols. This unit can work wilh any amplilier from 1W 
to 200W! 

Kit includes 70 pes. driver transistors, 36 pes. 
matched 4-color LED, all other electronic compon- 
ents, PC board and front panel. 



MARK IV KIT $31.50 




30 W 30 W STEREO 
HYBRID AMPLIFIER KIT 

It works in 12V DC as well! Kit includes 1 PC SANYO 
STK-043 stereo power amp, IC LM 1458 as pre amp, 
all other electronic parts, PC Board, all control 
pots and special heat 
sink for hybrid. Power 
transformer not in- 
cluded. If produces ultra 
hi-ii output up lo 60 
watts (30 watts per 
channel) yet gives dui 
less than 0.1% total har- 
monic distortion between 
$32.50 P.R KIT IQQMz and 10KH?. 




BATTERY POWERED 
FLUORESCENT LANTERN 

MODEL 80S R FEATURES 

3- Circuitry: designed for operation py high 
efficient, high power silicon transistor 
which enable illumination maintain in a 
standard level even the battery supply 
drops to a certain low voltage. 
• 9" 6W cool/daylight miniature fluores- 
cent tube. 
■ 8 x 1,5V UM-1 (size D) dry cell battery. 
■ Easy sliding door for changing batteries. 
£m so fa ' Stainless reflector wilh wide angle in- 
mu.ou m creaS j n Q inmination of the lantern. 



STEREO 



AMPLIFIER 



ill lu jiii Hi 



Mb 




60 W 



60 W 



COMPLETED UNIT -NOT A KIT! 

OCL pre amp. 5 power stereo amp. with bass, mid- 
dle, treble 3-way lone control. Fully assembled and 
tested, ready to work. Tolal harmonic distortion less 
than 0.5% at lull power. Output maximum is 60 
watts per channel at 8!!. Power supply is 24 - 36V 
AC or DC. Complete unit. Assembled $49.50 ea. 

Power transformer S 8.50 ea. 



5W AUDIO AMP KIT 

3 2 LM 330 with Volume Control 
Mill i T PowBr Suply 6 16V DC 
ONLY $6.00 EACH 



PA 

u 



Tvoe M0-52E 



PROFESSIONAL 
PANEL METERS 

A. 0-50 DA 9. 50 ea. 

II. 0-30VDC 8.50 ea. 

C. 0-50V0C 8.50 ea. 

D. 0-3ADC 9.00 ea. 

E. 0-100V0C 0.00 ea. 



All meters white lace with black 
scales. Plastic cover. 



msaaw o.s" led umi 

ALARM CLOCK MODULE 

ASSEMBLED! NOT A KIT! 

Features: * 4 digits 0.5" LED Displays » 12 hours 
real lime format * 24 hours alarm audio output 
• 59 min. countdown timer • 10 min. snooze control. 
ONLY $7.00 EACH 
SPECIAL TRANSFORMER 
FOR CLOCK 
(FREE) 



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DIGITAL AUTO 
SECURITY SYSTEM 



4 DIGITS 
PERSONAL CODE 



SPECIAL $19.95 




- proximity triggeret 
• voltage triggered 

- mechanically triggi 
This alarm protects you and Itself' Entering pro- 
le ctcd area will set it olf. sounding your car horn 
or siren you add. Any change in voltage will also 
Irigger the alarm inlo action. If cables within pas- 
senger compartment are cut. the unit protects Itsell 
by sounding the alarm. 3-WAY PROTECTION! 

All unils factory assembled and tested - Not a kil! 



A NEW LED ARRAY AND 

DRIVER FOR 

LEVEL METERS 

This series covers a wide range of level indication 
uses, output and input voltage, time related change, 
temperature, light measurement and sound level. The 
problem ol uneven brilliance often encountered with 
LED arrangements as well as design problems caused 
by using several units of varying size are substan- 
tially reduced 12 LEDs in one bar: 
LED ARRAY 
6L-112R3Red. Red. Red $5.50 

GL-112N3 Green, Yellow, Red $6.50 
GL-112M2 Green, Green, fled $6.50 
GL- 1 1 263 Green. Green , G ree n $6.50 



Z.2B" 

LED DRIVERS " 

1R 2406G Is an I.C. specially designed to drive. 12 
LED. The number of LED is lineally illuminated ac- 
cording to the control voltage input terminal 21 . 
Operating voltage is 9 12V D.C. 55.35 each 
DUEL CHANNEL VU METER 
P.C. BOARD AVAILABLE AT $4.50 EA. 



PROFESSIONAL FM 
WIRELESS MICROPHONE 

TECT model WEM-1 6 Is a factory assembled FM wire- 
less microphone powered by an AA size hattery. 
Transmits in Ihe range of B8-108MHz with 3 transis- 
tor circuits and an omni-directional electric conden- 
ser. Element buitt-ln plastic tube type case: mike is 
6'A" long. With a standard FM radio, can be heard 
anywhere on a one-acre lot: sound quality was 
Judged very good. 

$16.50 



FLASHER LED 

Unique design combines a jumbo red LED with an IS 
(lasher chip in one package. Operates directly from 
5V-7V DC. No dropping resistor neded. Pulse rate 
3 Hz @ 5V 20mA. _^___ 

2 far $2 .20 - - 

BIPOLAR LED RED/GREEN 

2 colors in one LED, green and red, changes color 
when reverse voltage supply. Amazing! 
2 FOR $1.60 



LCD CLOCK MODULE! 

■ 0.5" LCD 4 digits display - XTal controlled cir- 
cuits • D.C. powered (1.5V battery) ■ 12 hr. or 24 hr. 
display ■ 24 hr. alarm sel ■ 60 mm. countdown timer 
• On board dual back-up lights ■ Dual time zone dis- 
play • Stop watch function. 

NIC12dO(12hr) $24.50 EA. , 
N1CZ40O (24 hr) $26.50 EA ■ 



WANT TO BUILD YOUR 

OWN BLACK MAGIC BOX 

ON TOP OF THE TV FOR 

FIRST RUN MOVIES? 



We have all the parls Including hard to lind 

UHF variactor tuners and P.C. board. 

Call us for more information. 



FLUORESCENT LIGHT 

DRIVER KIT 

12V DC POWERED 
Uffhts up 8 — 15 Wall Fluo- 
rescent Light Tubes. Ideal 
(or cancer, outdoor, auto or 
boat. Kit includes high volt- 
age coil, power transistor, 
heat sink, all other eleclro- 
Witti Case Only nic parts and PC Board, light 
S6.50 Par Kit tube no 1 1 ncl u ded I 




SUPER FM WIRELESS 
MIC KIT — MARK 111 

This new designed circuit uses high 
FEQ. FET transistors with 2 stages 
pre amp. Transmits FM Range {88- 
120 MHz) up to 2 blocks away and 
with the ultra sensitive condenser 
microphone thai comes with the kil. 
allows you to pick up any sound 
within 15 It away! Kit includes all 
FMC-105 electronic parts. OSC colls, and P.C 
S11.S0 PEfl KIT Board. Power supply 9V DC 




PRESS-A-LIGHT SELF 
GENERATED FLASHLIGHT 

EXCLUSIVE 1 1 S3.9S ea Never worry about battery, 

^ Model F-179 because il bas none! Easy 

^ to Carry tn pockel and bandy 

^| ^^ In use. Idea! tor emergency 

light. It generates its own 

electricity by squeezing grip 

lever. Put one in your car. 

boat, camper or home. You 

may need il some timet 




ELECTRONIC DUAL 
SPEAKER PROTECTOR 

Cut off when circuit is shorted 
or over load to protect your 
amplifier as well as your 
speakers. A must tor OCL 
circuits 

KIT FORM 
S8.75 EA. 




'FISHER" 30 WATT 
STEREO AMP 



m 



Super Buy 
Only St 8.50 



MA1NAMP(15Wx2) 
Kit Includes 2 pes. Fisher PA 
30 1 Hybrid IC all electronic parts 
with PC Board. Power supply ± 
16V DC [not Included). Power 
band with (KF 1% =t 3dB). Volt- 
age gain 33dB. 20H* - 20KHz 



UNIVERSAL 
PROJECT BOARD 

All P.O. boards are made Irom high quality phenolic, 
predrilled in differed patterns (or different purpose. 
All boards 1/16" single sided copper. Hole spacing is 
slandard 0.1". Fils all kinds of I.e. transistors, capa- 
citors and resistors. Ideal (or school projects, engineer- 
ing designs and prototyping 



■ w-n-r j. 



SB072 




M-34 



CIRCUIT FIT 



BEL101 



BEL202 



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as-xr 


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vaw 


S1.25 E.» 


be uo: 


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St .25 EA 


Rl"! "''J 


2V'v5V 


SI .25 Ea 



PUSH-BUTTON SWITCH 

N/Open Contact 
,_;-, Color: fled. White, Blue. Green. Black 

*3jv 3/11.00 

j^ N 'Close also Available 

^F 50c each 

LARGE OTY. AVAILABLE 



HEAVY DUTY 
VjS CLIP LEADS 

Vi 10 pairs — 5 colors Ailigalor clips on a 
22" long lead ideal for any testing. 
$2.20/paclt 



BATTERIES 

PK/S10.00 I ~j — __^ NICKEL CADMIUM 
2 PKS/S19.00 L^_ I f~ — -^ 9ATTERY 




ILLUSTRATED 
LESS COVER 

Oiitial: 3 6 Villi @ 3 (.mp/Haiir. Consists ol I hit a tit*. 
I 2 Vol I "0 1 : lizi Nic He I Cum rum Cells stidttd ana" plnlic 
turn encapsulated Tibs are piovidro it each end tar elec- 
trical connection* The individual celts can de cut apart it 
tesiretf Rated recharge /ate is 30 mA. 14-ic hours. Size 
V'*" dia t 7 H long Ne* Sheg wi each pack, 1 lb 



"C" SIZE BATTERY PACK 

»SlP. 10 C size ni-cd ballery in dng pack. 

.mICm, gives out 12.5V DC 18 amp pet 
y 1^'jpgW' hour. All fresh CDde. pull-out from 
^-< I 1 4 sjmovie cameras Can be disconnec- 



j^ed to use as single c celts Hard 
.atVli} Imd $15,00 per pack of 10 batteries 



ELECTRONIC ALARM SIREN 

COMPLETE UNIT 
Ideal for use as an Alarm Unit 
or hookup to your car back-up to 
make a reverse indicator. Light 
Output up to 130dB. Voltage sup- 
AU-999 S7.5Q ply 6 12V 



k 



SUB MINIATURE 
TOGGLE SWITCH 

SPST2 FOR 2JOSPDT2 FOR 3.20 
6 AMP 125V AC CONTACT 



^TRANSFORMERS 

ALL 117 VOLT INPUT 

JOV 4 AMP S8.50 EA. 

36V CT 3 AMP S10.50 EA. 

4BV CT 3 AMP $10.50 EA. 

24V CT 0.5 AMP S3.00 EA. 

18V CT 0.5 AMP S3.O0EA. 

12V CT 0.5 AMP S2.50EA. 

6.3V D.5 AMP S2.00 EA. 



*%? 



AC POWER SUPPLY 

Wall Type Transformer 
12V AC Output 200 MA S2.75 EA- 

16VCTAC Output 10OMA S2.10 EA. 
SVDC Output 120 MA SI. 90 EA. 

12V 0C Output 100 MA 51.90 EA. 



ULTRASONIC 
7\ SWITCH KIT 



Kit includes the Ultra Sonic Transducers. 2 PC Boards 
lor transmitter and receiver. All electronic parts and 
instructions. Easy to build and a lot of uses such as 
remote control lor TV. garage door, alarm system or 
counter. Unit operates by 0-12 0C. $15.50 



COMPLETE TIME MODULE 

0.3" digits LCD Clock Module witb month 

and date, hour, minute and seconds. As 

well as stop watch I unction!! Battery 

and back up tight is with the module. 

Size of the module is 1" dia. Ideal (or 

use in autp panel, computer, instrument 

and many others' S8.95 EACH 




SOUND ACTIVATED SWITCH 

.. All parts completed on a PC Board 

*n±. SCR will turn on relay, buzzer or 

■■TV trigger other circuij for 2 - 10 sec. 

^WKeji (adjustable). Ideal tor use as door 

^^■B alarm, sound controlled toys and 

^» many other projects. Supply voltage 

$1.75 ea. 1.5V 9V D.C. 1 (or $3.00 



FM WIRELESS MIC KIT 

II is not 3 pack of cigarettes. II Is a 
new FM wireless mic kil! New de- 
sign PC board tits into a plastic 
cigarette box (case Included). Uses 
a condensor microphone to allow you 
to have a better response in sound 
pick-up. Transmits up tp 350 ft.! 
With an LED indicator to signal the 
unit is on =FMM2 KIT FORM $7.95 




A% FORMULA INTERNATIONAL INC. 

fife ™a> I 1 — tmht-.Ni »kC nAntkLifce c«AAd?l 1 S« 




REGULATED DUAL 
VOLTAGE SUPPLY KIT 

i4 30V DC 800 MA adjustable, fully regulated 
by Fairchild 78MG and 79MG voltage regulator I.e. 
Kil Includes all electro- 
nic parts, filter capaci- 
tors. I.e.. heat sinks 
and P.C. board. 
$12.50 PER KIT 



AA SIZE NI-CD SPECIAL SALE 
mm jim.il ni \,hr 4 F OBS 5 00 

RECHARGEABLE BATTERIES 

LIMITfD QUANTITY AVAILABLE 



POCKET SIZE 
AM-FM RADIO 

TR-945 with 
LED TUNING EYE 



flew design (ody with see 

thru speaker grill. 

SPECIAL PRICE $16.50 EACH 




TR-945 



POWER SUPPLY KIT 

0-30V O.C. REGULATE0 
Uses UA723 and 2N3055 Power 

TR output can be adjusted (rom 
0-30V. 2 AMP. Complete with PC 
board and all electronic parts. 
Transformer for Power Supply. 
2 AMP 24V i 2 SB.5Q 



0-30 Power Supply 
$10,50 each 



I.C. TEST CLIPS 

Same as the E-Z clips « .r 
With 20" Long Leads **•'* 

tn Black and Red Colors per pair 



SOUND GENERATOR I.C. 

Creates almost any type of sound — gun shot, ex- 
plosion, train, car crash, star war. birds, organ ext. 
A built-in audio amplifier provides high level output. 
Operates from one 9V battery, 28 pin 
dip: we supply the datas. $z,gg EACH 



ELECTRONIC SWITC 



CONDENSER TYPE 

Touch On Touch Off 

uses 7473 I.C. and 

12V relay 

$5.50 eaeh 




1 WATT AUDIO AMP/* 

All parts are pro-assembled on a J 

mini PC Board. Supply Voltage 6 
9VD.C. SPECIAL PRICE S1.95 ea. 



*r 



LOW TIM DC STEREO 
PRE-AMP KIT TA-10 20 

Incorporates brand-new D,C. design that gives a 
frequency response from 0Hz — lOOKHz z:0.5d8! 
Added features like tone defeat and loudness control 
let you tailor your own frequency supplies to eli- 
minate power fluctuation! 

Specifications: ■ T.H.O. less than .005% ■ T.I.M. 
less than .005% ■ Frequency response: DC to 100KHi 
iO.SdB ■ H1AA deviation: =Q.2dB • S/N ratio: bet- 
ter than 70dB • Sensitivity: Phono 2MV 47K/Aux. 
100MV 10BK ■ Output level: 1.3V • Max. output: 15V 
• Tone control: bass ^10dB @ 50Ki/treble =:10dB 
@ 15Hj ■ Power supply: ±24 O.C. ® 0.5A 
Kit comes with regulated power supply, all you need 
is a 48V CT. transformer @ 0.5A., 
ONLY $44.50 
X 'former 
$4.50 ea. 




SOLID STATE 
ELECTRONIC BUZZER 

Mini size 1"x J A" xW 

Supply voltage 1.5V -12V 

Idea! for Alarm or Tone Indicator 



. ... , ,., — , unwiaisLM. 

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CAPACITOR 

111X1 MFD 330 VOLTS 



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4 F xV DOUBLE SIDED EPOXY BOARD Irtfi' thick 








EPOXY glw UKtwbowd 

Iflfl* (Jewish. WIG' t^yaring 4yj"x W $1.95 




74500 - .30 74S2Q - .40 74S153 ^ 1.10 
7*502 - -30 74S30 - .*C 74S151 1,25 
7*S05 - .45 74S32 - -*Q 74S157 - 125 
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7 WATT LD 65 LASER DIODE IR SS.95 



26 Yvm tnlrs Hisd Pulw (SG 2C06 equlv.) 

Luh Dkxk tSjmc shwt indbdcdl 124.96 

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100. &K r 10K.»iX, 2S0K h 1 M*9. *.76«ftCri . .3/2.00 

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fp 100 PHOTO TRAXS 

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fltt> OREENaiPOLftflLEO'i 
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13.15. 18, or 22V 



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TRANSISTOR SPECIALS 

2JJI30JrTjPCiET05i 
?K*MA PfVJF CjE TO 5, 

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2NJ3l3J4P^Si T03PF 

3M1 430,4^5)705 

IMJre^MPH&TOifla 

PJiUJMfUSi -"016 

3^Kfi5HWi5iT03 

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lUbttG hH Si TO-2M 

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1.40 


200 


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400 


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1.65 


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600 


1,30 


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4.40 



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15 PIN .22 2a PIN .40 
IS PIN ^S 4DPIN .B0 



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Si 1010 G 10 WATTE * 7.60 

SI1020G20WATTS »13-T6 

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FLAT (COlLOn. CODE Dl 

y:.:. ■:. ■ m 

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COMVECTORS 



DB25Prru!te 13.25 

DB 25S tvmtto ■ K25 
HOODS 51.60 



HJOPAV 1 A LASER 95 



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1 a .01 uf 25V c&rarTtcdrK; capi 16^1.00. lOO^EflOO 



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ALCO MiPJLATURI TDOCU SWITCHES 
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SCR'S TRIACS 


109 


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P.O. BOX 74D 

SOMERV1LLE, MASS. 02143 TEL 1617) 547 7053 



WE SHIP OVER 85% 

OFOURORDERSTHE 

DAY WE RECEIVE THEM 



CIRCLE 31 ON FREE INFORMATION CARD 





Clock Ki^^locl^odule^^loseou^^^ . .. j-,, „j._^„« /-, Miners • Microprocessor & Supportf^B 

• Breadboarding & Testing Devices * Quality EjleCWOniC Components Eesistors • NETWORK Resistors ■ B H 

OK Products * Texas Instrument * Panasonic * National Semiconductor * PanaVice • linger • Diamond Tools * ]C Sockets^ 00 



INTEGRATED CIRCUITS 



TEXAS INSTRUMENTS GOLD TIME-TEMPERATURE 

EDGEBOARD CONNECTORS PROGRAMMABLE MODULE 



K-Series 




o 

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HANDLING CHARGES VOLUME DISCOUNT 

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CIRCLE 35 ON FREE INFORMATION CARD 



to 
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ELECTRONIC TOOL 




OVER 5,000 HARD-TO-FIND PROD- 
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AND REPAIRING ELECTRONIC EQUIP- 
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ILLUSTRATED WITH PHOTOS, DE- 
TAILED DESCRIPTIONS, AND PRICES. 
FAST, OFF-THE-SHELF DELIVERY. 
ALL MERCHANDISE GUARANTEED. 
EASY TO ORDER BY PHONE OR 
MAIL. 



Here's some of the types of products 
you'll find In this complete catalog: 

• Precision cutters and pliers • Complete 
line of soldering supplies • Test in- 
struments • Tool kits, cases & boxes, 

• Solder-suckers • Wire strippers * Wire 
wrap tools • Anti-static handling mater- 
ials • Circuit board holders • Ultra- 
sonic cleaners • Technician's benches 

• Optical inspection devices • Special 
electronic adhesives • Power tools 
Plus much, much more. 



Contact East, Inc., Dept. 4072, 7 Cypress 
Dr., Burlington, MA 01803 



Rush me your FREE catalog. 
Name 



Address 



City 



State. 



Clip & mall coupon to: 
Contact East, Inc. 

Dept. 4072 
7 Cypress Dr. 
Burlington, MA 01803 



Zip_ 



152 



CIRCLE 13 ON FREE INFORMATION CARD 



ADVERTISING INDEX 

RADIO-ELECTRONICS does not assume 
any responsibility for errors that may 
appear in the index below. 

Free Information Number Page 

34 AMC Sales 144 

19 AP Products, inc 25 

64 Actire Electronics 129 

8-9 Admitted Computer Products 142-143 

— Advance Electronics 12-13,22, 113 

44 All Electronics 150 

18 American Antenna Cover 4 

20 R & K Precision Dynascan Corp 27 

— Bagnali Electronics 131 

— Karel Barta „„, 152 

12 Beckman 33 

— Bullet Electronics 146 

— Burdcx Security J28 

43 CFR Associates 134 

72 Cambridge Learning Inc 117 

69 Cascade Labs 146 

32 Chancy Electronics 144 

— CIE— Cleveland Institute of 

Electronics 34-37 

— Command Productions 131 

45 Concord — Computer Components .. 130-131 

13 Contact East 152 

5 Cooper Group ...„.,„„. „ Cover 2 

— Dage Scientific 128 

— Dcltroniks 131 

70 Dia mondback Electronics 138 

35 Digi-Key 151 

61 Discwasher 28 

56 E1CO 1 15 

— ETCO 130 

1 7 80-O.S. Journal 144 

41 Electronic Parts Supply .., 138 

— Electronic Technology Today 32 

— Electronics & Control Engineers' Book 

Club— McGraw-Hill Book Di*.„ 118-121 

36 Electronics Book Service 29 

63 Electronics Technical Institute 28 

67 Enterprise Development Corp 122 

— Fair Radio Sales 152 

46 Fluke 7 

— Fordbam Radio Supply 147 

22-23 Formula International 148-149 

71 Gladstone Electronics 1 14 

58 Global Specialties .,.,,,. 2 

— Global TV Electronics 128 

47 Godbout Electronics 146 

— Grantham College of Engineering 122 

53,52,54 Heath 9, 30-31, 44, 125 

77 Hickok Electrical Instruments 15 

57 Hitachi Densbi , 24 

— Information Unlimited. 130 

— Interface Age.. 73 

24 International Crystal Mfg. Co 127 

48 International Electronics Unltd... 141 

— IS & A I 

29-30 Jameco Electronics 136-137 

27 Jensen Tools, Inc. ...,„,,. ......,,,..- 126 

39*40,38 Mercury International Sales 

Group , 5, 41, 85 



25 

51 
60 
59 
61 



11 

42 
65 
33 
21 

6 
49 

75 
14 
78 
26 

68 
15 



10 

76 

31 

7 
3 

4 
2 
37 



Meshna 134 

Micro Ace 133 

Micro Management Systems 139 

Micro Mart 138 

MTI— Mobile Training Institute 126 

Mosaic Electronics 122 

NJS Technology, Inc., 1 1 

National Radio Institute (NRI|— D)t. of 

McGraw-Hill 16-19 

National Technical Schools 100-103 

Netronics 39 

O.K. Machine & Tool ,..,. 21 

OnComputing 26 

Optoelectronics Cover 3 

PAIA 20 

PPG, Inc , 20 

Pac-Com 127 

Panavise...., 38 

Percom Data Co,,,,,,,.,,,..,,..,...... 50 

Poly Paks 144 

Quest... , 145 

Quietrole 122 

RCA 14, 23 

Radio Shack 135 

Ramsey Electronics „,..,,..„ 140 

Sabironics, ....,...„,...,.......,... Ill 

Howard W. Sams 46 

Schober Organ , 24 

SGL Waber 38 

Sbuie Brothers 40 

Sinclair Research Ltd. 43 

Solid State Sales !50 

Spacecoast Research... ,;,.„. 128 

Steven Products 134 

Testek 1 15 

Tronics 2000 , 86 

Vector , 127 

VIZ Mfg. Co 42 

Wersi Electronics 126 



HIGHLY 
PROFITABLE 



ELECTRONIC 



ONE-MAN 
FACTORY 



Investment unnecessary, knowledge not re- 
quired, sales handled by professionals Ideal 
home business Write today for facts' 
Postcard will do. Barta-RE-H, Box 248, 
Walnut Creek, CA 94597. 



Govt. SURPLUS 
ELECTRONIC 
EQUIPMENT 



New ITEMS . . . New BARGAINS! 

rorr upon request.' 

rflEE Send today for FREE copy of 
CATALOG WS-80 and Supplement. Dept. RE 



FAIR RADIO SALES 

1016 E EUREKA • Box DOS ■ LIMA. OHIO ■ 45602 



A LIFETIME GUARANTEE AND 1 1 OTHER REASONS TO BUY 
AN "OPTOELECTRONICS" FREQUENCY COUNTER 






1. SENSITIVITY: Superb amplifier circuitry with performance 
that can't be matched at twice the price. Average sensitivity 

of better than 15 mV from 10 Hz to 500 MHz on every model 
and better than 30 mV from 500 MHz to 1.1 GHz on the Series 
801 0A and 8013. 

2. RESOLUTION: 0.1 Hz to 12 MHz, 1 Hz to 50 MHz, 10 Hz 
over 50 MHz. 

3. ALL METAL CASES: Not only are the heavy gauge aluminum 
cases rugged and attractive, they provide the RF shielding 
and minimize RFI so necessary in many user environments. 

4. EXTERNAL CLOCK INPUT/OUTPUT: Standard on the 8010/ 
8013 series and optional on the 7010 series is a buffered 

10 MHz clock time base input/output port on the rear panel. 
Numerous uses include phase comparison of counter time 
base with WWVB (U.S. National Bureau of Standards). Stand- 
ardize calibration of all counters at a facility with a common 
10 MHz external clock signal, calibrate scopes and other test 
equipment with the output from precision time base in 
counter, etc., etc. 

5. ACCURACY: A choice of precision to ultra precision time 
base oscillators. Our ± 1 PPM TCXO (temperature compen- 
sated xtal oscillator) and ± 0.1 PPM TCXO are sealed units 
tested over 20-40 "C. They contain voltage regulation circuitry 
for immunity to power variations in main instrument power 
supply, a 10 turn (50 PPM) calibration adjustment for easy, 
accurate setability and a heavily buffered output prevents 
circuit loads from affecting oscillator. Available in the 8010 and 
8013 series is our new ultra precision micro power proportional 
oven oscillator. With ±.05 PPM typical stability over 10-45°C, 
this new time base incorporates all of the advantages of our 
TCXO's and virtually none of the disadvantages of the tradi- 
tional ovenized oscillator: Requires less than A minutes 
warm-up time, small physical size and has a peak current 
drain of less than 100 ma. 

6. RAPID DISPLAY UPDATE: Internal housekeeping 
functions require only .2 seconds between any 
gate or sample time 

MODEL 7010A 600 MHz I 



period. At a 1 second gate time the counter will display a new 

count every 1.2 seconds, on a 10 second gate time a new count 

is displayed every 10.2 seconds. (10.2 seconds is the maximum 

time required between display updates for any resolution on 

any model listed). 

7. PORTABILITY: AH models are delivered with a 115 VAC 

adapter, a 12 VDC cord with plug and may be equipped with 

an optional ni-cad rechargeable battery pack installed within 

its case. The optional Ni-Cad pack may be recharged with 12 

VDC or the AC adapter provided. 

a. COMPACT SIZES: Sta1e-of-!he-Art circuitry and external AC 

adapters allowed design of compact easy to use and transport 

instruments. 

Series 8010/8013: 3" H x 7-1/2" W x 6-1/2" D 

Series 7010: 1-3/4" H x 4-1/4" W x 5-1/4" D 

9. MADE IN U.S.A.; All models are designed and manufactured 
at our modern 13,000 square foot facility at Ft, Lauderdale, 
Florida. 

10. CERTIFIED CALIBRATION: All models meet FCC Specs 
for frequency measurement and provided with each model is a 
certificate of NBS traceable calibration. 

11. LIFE TIME GUARANTEE: Using the latest State-of-the-Art 
LSI circuitry, parts count is kept to a minimum and internal 
case temperature is only a few degrees above ambient 
resulting in long component life and reliable operation. (No 
custom IC's are used.) To demonstrate our confidence in these 
designs, all parts (excluding batteries) and service labor 
are 100% guaranteed lor life to the original purchaser. 
(Transportation expense not covered). 

12. PRICE: Whether you choose a series 7010 600 MHz 
counter or a series 8013 1.3 GHz instrument it will compete 
at twice its price for comparable quality and performance. 

MODEL8010AV80131.1 GHz/1 .3GHz 



i om« mouther couHtis 



l D. n n n n n n n 



IODEL 

7010A 

'010 IA 

BOIQA 

IO10 IA 

010.Q5A 

80131 

B0 



fD.OBBQQQ.0 



UT. CL*. 4U 



optotl.ctronicm inc. 



ImM m» mm mm ' — — ' 
■ fill: III! 

- 1 ' OAT. T,— ,—- _ 



* J 



ic£ tofe 



Wl 



HANGE 
(From 10 Hi) 


10 Ml 
STABILITY 


600 MHZ 


UPPM 

= 1 PPM 


1 IGHZ 


I IPPM 
- 1 PPM 
i 05 PPM 


i ZGnt 


±. 1 PPM 
^ 05 PPM 



AVG. SENSITIVITY 
10 Hi to 500 MHi 500MHrto1.IGHl 



RESOLUTION 



,40 



TIMES 



EXT. CLOCK SENSITIVITY Nl CA 

12 MHz BOMHl Ml*. Frcq. INPUT/OUTPUT CONTROL BATTERY PACK 



•- 1 PPM/YR TCXO 



ERIES 701 QA 

7Q1QA 600 MHz Counter 1 PPM TCXO $199.95 

70I0.1A 600 MHz Coil filer -0.1 PPM TCXO $24995 

IPTIONS 

Nih HanOTe'Tilt Baiiinni show $2 95 

Ni-Cafl 701 Nr Cad Satiety Pack i. Charging 

Circuitry Installed inside Unit $19 95 

EC-70 Externa! Clock InpulfOulpul $35 00 

CC 70 Carry Case - Paused Black Vinyl $9 95 





SERIESB01QA/8013 



rfSClOA t IGHzCounler-l PPM TCXO $399 00 

H8QI0IA 1 1 GHz Counter -0.1 PPM TCXO $45000 

*S0IO,O5A 1.3 GHz Counter -.05 PPM Ouen $499.00 

MJ013 I 1 SGHzCounlerO 1 PPMTCXO $550.00 

KB013.O5 1 3 GHz Counter-. 05 PPM Oven $599 00 

OPTIONS 

KNiCartriOt Ni Can Baiter, P mo W995 

Circuitry Installed Inside Unil 

KCC80 C3rry Case Padded Black Vinyl $9.95 



ACCESSORIES 
•TA-100 



Tel esc ope an te nna w 1 1 h 
right angle BNC 
Probe. 50 Ohm. IX 
Probe. Lo~Pass 
Audio Usage 
Probe MiZ 
General Purpose 
HLFM 1 110 Low Frequency Multiplier 
X 10. X IOO.XIOjQO 
For High Resolution ol Audio pieq 



*P (00 

■p tot 



=i- io: 



$ 99f 

$139; 

Sib 9! 
$16.9! 



5821 N.E. 14th Avenue, Fort Lauderdale, Florida 33334 1 "800-327-59 1 



tor shipping, handling and insurance la a fn-nimurnol S10 00 An alher orders | 

nltfir»tlnn tAO *1 nfl Clor.rln nrriort 3j1(( J 1 . <laff* I ri , Prnr*y"m:i| rHF>f.k*i tTlilftt t.lt*AT fcfff f>fC COrCdS ii< V r >tllL>QGlC] 



FROM FLORIDA (305) 771-3051/; 



In one year our K 4 P antenna 

has become the largest selling 

CB antenna in the world"! 

1. It's more 2. It's made 

expensive . . . better. . . 

^■f Af# suggested retail 

And when you 

pay more, 

you expect more! 









MORE PERFORMANCE 

The K40 is guaranteed to 
transmit further or receive 
clearer than any antenna it 
replaces. We know it will. 
We've tested It with 771 
CS'ers just like you for one 
year. 

MORE FLEXIBILITY: 

You can fit your K40 to any 
mounting surface. It will fit 
any vehicle you'll ever own! 
That includes choppers, dune 
buggies, gutters, mirror 
mounts,iuggageracks,trunks. 
hatchbacks, through roofs, 
semis, pick ups and RV's. 

MORE QUALITY: 

It's not imported. Ifs not 
made in Taiwan, Korea or 
Japan, ifs American made in 
an American town. It's made 
with better materials that 
cost more and by profession- 
al people we pay more. And 
we designed it right 
herein the U.S.A. 

'Including option- 
al mounts at extra 
cost 



...This 

Antenna 
is so 
DYNAMITE 
yon receive a 




3. It's proven best! 

...Here's what the leading CB 
publications said. 

CB TIMES: ". . . it's not often that a product bursts onto the mar- 
ket scene, dominates and improves CB'ing for everyone. American 
Antenna and the K40 are doing it — repeated tests showed the K40 
could out-perform the major competitive brands." 
RADIO-ELECTRONICS: "The results of our tests showed 
that, in three different positions of the monitoring receiver, Hie 
model K40 equated or out-performed the competitive antenna. 
Apparently, American Antenna's advertising is not merely Madison 
Avenue showmanship." 

PERSONAL COMMUNICATIONS: an impressive 

95% of the trials, the K40 out-performed the existing mobile anten- 
nas. We had to try one for ourselves, 

", . . in every case, the K40 either equaled or out- performed its 
competitor. 
"No ifs, ands, or buts! The K40 Antenna from American Antenna would have to 
be just about the best antenna around . 

CB MAQAZINE: "Introduced in October, 1977, the K40 quickly became the 
top seller and in mid 1 978, became the number one selling antenna In the nation " 

...Here's what CB'ers all 
across the country said. 

ANTENNA SPECIALISTS: ". . . truck driver and CB'er for 
1 years . . . 50% further than my M41 "Big Momma'." 

—J.H. Conett. 207 UcFee, Bastrop. LA 
AVANTI: "I'm an electronic technician with a Second Class 
FCC license ... I was able to transmit 70% further and tune 
the SWB 75% lower than my Avanti. " 

—H.R, Castro. VftB, Monsarmnto D-67, Saunas. Puarto Rico 

PAL: ", . . 20% better in transmission and 
reception than my 5/8 wave Pai Firestik." 

—John A. Bkrm. Box 446. Zatienolpta, PA 

SHAKESPEARE: ". . . I've been a CB'er for 
three years and the K40 is the best I've ever 
had. Better in reception and transmission than 
my Shakespeare." 

— H. Bactwt Jr., tS Kino JW„ Park Ridge, HJ 

HUSTLER: "Compared to my Hustler XBLT- 
4, the K40 can consistently transmit 40% 
further and the reception was better. The K40 is 
the perfect way to complete aCB system." 

—Joroma R Brown, 7800 S. Lrtdnr, Btrrbank, IL 



(SPECIAL NOTE) 
IF YOU'RE A 



^14MKUJ^{ 




Out K40 Dealers will be hap- 
py to sell you any of the older 
style and less expensive an- 
tennas thai are great bar- 
gains for any beginning CB'er. 



ELGIN, IL 60120 

:'COPypK3HT AMERICAN ANTENNA | I ■ 



POWER! 

. Sold exclusively by^ ^jf American K 40 Dealers throughout the U.S. & Canada. 



CIRCLE IB ON FREE INFORMATION CARD